mysql2 can't be built on Catalina due to -lssl failing

[chrisseaton]

We're unable to build mysql2 on macOS Catalina at the moment. I think this is the problem:

% /usr/local/Cellar/mysql-client/5.7.10/bin/mysql_config --libs
-L/usr/local/Cellar/mysql-client/5.7.10/lib -lmysqlclient -lssl -lcrypto

So the Homebrew libmysqlclient links -lssl but nothing says to look in /usr/local/Cellar/openssl/1.0.2t/lib. I think it worked before as /usr/lib contains a libssl, but /usr/lib is not on the path now. So I think that's a Homebrew bug? Does anyone else have an opinion on that?

What I've done to workaround for now is to modify mysql_config in place

- libs="-L$pkglibdir"
+ libs="-L$pkglibdir -L/usr/local/Cellar/openssl/1.0.2t/lib"

[eregon]

Thanks for the report.

Does installing mysql work on MRI on macOS Catalina?
Can you see which libssl it links to if it does, with otool -L path/to/mysql.bundle?

This might be due to eager checks when linking on macOS, I'll make a PR to make them more lazy like on MRI (-Wl,-undefined,dynamic_lookup). That might help, but I'm not sure it's enough for this case.

[chrisseaton]

I can install with MRI on Catalina.

% otool -L ~/.gem/ruby/2.6.5/gems/mysql2-0.5.2/lib/mysql2/mysql2.bundle 
/Users/chrisseaton/.gem/ruby/2.6.5/gems/mysql2-0.5.2/lib/mysql2/mysql2.bundle:
	/usr/local/opt/mysql-client/lib/libmysqlclient.20.dylib (compatibility version 20.0.0, current version 20.0.0)
	/usr/local/opt/openssl/lib/libssl.1.0.0.dylib (compatibility version 1.0.0, current version 1.0.0)
	/usr/local/opt/openssl/lib/libcrypto.1.0.0.dylib (compatibility version 1.0.0, current version 1.0.0)
	/usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1281.0.0)

So it should be linking to the one inside Homebrew as we'd expect, and it looks like it's mysql_config that is misconfigured, would you agree?

Delaying won't help, as it still wouldn't know where to find libssl at runtime (and I've dealt with quite a few weird bugs related to ignoring undefined symbols in gems recently.)

[eregon]

I can install with MRI on Catalina.

Is that with your change to mysql_config though?
I wonder how mysql_config or mysql's extconf.rb finds the path to libssl.

[chrisseaton]

It install on MRI without my change. I'm not sure how it's working there either.

[eregon]

https://github.com/brianmario/mysql2/blob/0.5.2/ext/mysql2/extconf.rb doesn't seem to link to libssl explicitly, only through mysql_config --libs.

On Linux I see on MRI:

$ mysql_config --libs
-L/usr/lib64/ -lmariadb -lz -ldl -lm -lpthread -lssl -lcrypto
$ ldd /home/eregon/.rubies/ruby-2.6.2/lib/ruby/gems/2.6.0/gems/mysql2-0.5.2/ext/mysql2/mysql2.so
	linux-vdso.so.1 (0x00007fff047c7000)
	libmariadb.so.3 => /usr/lib64/libmariadb.so.3 (0x00007f871844f000)
	libz.so.1 => /usr/lib64/libz.so.1 (0x00007f8718435000)
	libdl.so.2 => /usr/lib64/libdl.so.2 (0x00007f871842f000)
	libm.so.6 => /usr/lib64/libm.so.6 (0x00007f87182ab000)
	libpthread.so.0 => /usr/lib64/libpthread.so.0 (0x00007f8718289000)
	libssl.so.1.1 => /usr/lib64/libssl.so.1.1 (0x00007f87181f3000)
	libcrypto.so.1.1 => /usr/lib64/libcrypto.so.1.1 (0x00007f8717f11000)
	libc.so.6 => /usr/lib64/libc.so.6 (0x00007f8717d4b000)
	/lib64/ld-linux-x86-64.so.2 (0x00007f87184ba000)

@chrisseaton Could you share the generated Makefile for MRI in
~/.gem/ruby/2.6.5/gems/mysql2-0.5.2/ext/mysql2/Makefile ?

[chrisseaton]

It appears in ldflags somehow

SHELL = /bin/sh

# V=0 quiet, V=1 verbose.  other values don't work.
V = 0
Q1 = $(V:1=)
Q = $(Q1:0=@)
ECHO1 = $(V:1=@ :)
ECHO = $(ECHO1:0=@ echo)
NULLCMD = :

#### Start of system configuration section. ####

srcdir = .
topdir = /Users/chrisseaton/.rubies/ruby-2.6.5/include/ruby-2.6.0
hdrdir = $(topdir)
arch_hdrdir = /Users/chrisseaton/.rubies/ruby-2.6.5/include/ruby-2.6.0/x86_64-darwin19
PATH_SEPARATOR = :
VPATH = $(srcdir):$(arch_hdrdir)/ruby:$(hdrdir)/ruby
prefix = $(DESTDIR)/Users/chrisseaton/.rubies/ruby-2.6.5
rubysitearchprefix = $(rubylibprefix)/$(sitearch)
rubyarchprefix = $(rubylibprefix)/$(arch)
rubylibprefix = $(libdir)/$(RUBY_BASE_NAME)
exec_prefix = $(prefix)
vendorarchhdrdir = $(vendorhdrdir)/$(sitearch)
sitearchhdrdir = $(sitehdrdir)/$(sitearch)
rubyarchhdrdir = $(rubyhdrdir)/$(arch)
vendorhdrdir = $(rubyhdrdir)/vendor_ruby
sitehdrdir = $(rubyhdrdir)/site_ruby
rubyhdrdir = $(includedir)/$(RUBY_VERSION_NAME)
vendorarchdir = $(vendorlibdir)/$(sitearch)
vendorlibdir = $(vendordir)/$(ruby_version)
vendordir = $(rubylibprefix)/vendor_ruby
sitearchdir = $(DESTDIR)./.gem.20191022-2519-1d3rqu8
sitelibdir = $(DESTDIR)./.gem.20191022-2519-1d3rqu8
sitedir = $(rubylibprefix)/site_ruby
rubyarchdir = $(rubylibdir)/$(arch)
rubylibdir = $(rubylibprefix)/$(ruby_version)
sitearchincludedir = $(includedir)/$(sitearch)
archincludedir = $(includedir)/$(arch)
sitearchlibdir = $(libdir)/$(sitearch)
archlibdir = $(libdir)/$(arch)
ridir = $(datarootdir)/$(RI_BASE_NAME)
mandir = $(datarootdir)/man
localedir = $(datarootdir)/locale
libdir = $(exec_prefix)/lib
psdir = $(docdir)
pdfdir = $(docdir)
dvidir = $(docdir)
htmldir = $(docdir)
infodir = $(datarootdir)/info
docdir = $(datarootdir)/doc/$(PACKAGE)
oldincludedir = $(SDKROOT)/usr/include
includedir = $(prefix)/include
runstatedir = $(localstatedir)/run
localstatedir = $(prefix)/var
sharedstatedir = $(prefix)/com
sysconfdir = $(prefix)/etc
datadir = $(datarootdir)
datarootdir = $(prefix)/share
libexecdir = $(exec_prefix)/libexec
sbindir = $(exec_prefix)/sbin
bindir = $(exec_prefix)/bin
archdir = $(rubyarchdir)


CC_WRAPPER = 
CC = clang
CXX = clang++
LIBRUBY = $(LIBRUBY_A)
LIBRUBY_A = lib$(RUBY_SO_NAME)-static.a
LIBRUBYARG_SHARED = 
LIBRUBYARG_STATIC = -l$(RUBY_SO_NAME)-static -framework Security -framework Foundation $(MAINLIBS)
empty =
OUTFLAG = -o $(empty)
COUTFLAG = -o $(empty)
CSRCFLAG = $(empty)

RUBY_EXTCONF_H = 
cflags   = $(optflags) $(debugflags) $(warnflags)
cxxflags = $(optflags) $(debugflags) $(warnflags)
optflags = -O3
debugflags = -ggdb3
warnflags = -Wall -Wextra -Wdeclaration-after-statement -Wdeprecated-declarations -Wdivision-by-zero -Wimplicit-function-declaration -Wimplicit-int -Wpointer-arith -Wshorten-64-to-32 -Wwrite-strings -Wmissing-noreturn -Wno-constant-logical-operand -Wno-long-long -Wno-missing-field-initializers -Wno-overlength-strings -Wno-parentheses-equality -Wno-self-assign -Wno-tautological-compare -Wno-unused-parameter -Wno-unused-value -Wunused-variable -Wextra-tokens
cppflags = 
CCDLFLAGS = -fno-common
CFLAGS   = $(CCDLFLAGS) $(cflags)  -pipe -Wno-bad-function-cast -Wno-conditional-uninitialized -Wno-covered-switch-default -Wno-declaration-after-statement -Wno-disabled-macro-expansion -Wno-documentation-unknown-command -Wno-missing-field-initializers -Wno-missing-variable-declarations -Wno-padded -Wno-reserved-id-macro -Wno-sign-conversion -Wno-static-in-inline -Wno-switch-enum -Wno-undef -Wno-unreachable-code -Wno-used-but-marked-unused $(ARCH_FLAG)
INCFLAGS = -I. -I$(arch_hdrdir) -I$(hdrdir)/ruby/backward -I$(hdrdir) -I$(srcdir) -I/usr/local/Cellar/mysql-client/5.7.10/include/mysql
DEFS     = 
CPPFLAGS = -DHAVE_RB_ABSINT_SIZE -DHAVE_RB_ABSINT_SINGLEBIT_P -DHAVE_RB_WAIT_FOR_SINGLE_FD -DHAVE_MYSQL_H -DHAVE_ERRMSG_H -DHAVE_CONST_MYSQL_OPT_SSL_ENFORCE -DHAVE_MYSQL_NET_VIO -DHAVE_ST_NET_VIO -DHAVE_CONST_MYSQL_ENABLE_CLEARTEXT_PLUGIN -DHAVE_CONST_SERVER_QUERY_NO_GOOD_INDEX_USED -DHAVE_CONST_SERVER_QUERY_NO_INDEX_USED -DHAVE_CONST_SERVER_QUERY_WAS_SLOW -DHAVE_CONST_MYSQL_OPTION_MULTI_STATEMENTS_ON -DHAVE_CONST_MYSQL_OPTION_MULTI_STATEMENTS_OFF -DHAVE_TYPE_MY_BOOL  -I/usr/local/opt/openssl/include -I/usr/local/opt/readline/include -I/usr/local/opt/libyaml/include -I/usr/local/opt/gdbm/include -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE -D_DARWIN_UNLIMITED_SELECT -D_REENTRANT $(DEFS) $(cppflags)
CXXFLAGS = $(CCDLFLAGS) $(cxxflags) $(ARCH_FLAG)
ldflags  = -L. -fstack-protector-strong -L/usr/local/lib -L/usr/local/opt/openssl/lib -L/usr/local/opt/readline/lib -L/usr/local/opt/libyaml/lib -L/usr/local/opt/gdbm/lib -Wl,-rpath,/usr/local/Cellar/mysql-client/5.7.10/lib
dldflags = -Wl,-undefined,dynamic_lookup -Wl,-multiply_defined,suppress -L/usr/local/opt/openssl/lib -L/usr/local/opt/readline/lib -L/usr/local/opt/libyaml/lib -L/usr/local/opt/gdbm/lib 
ARCH_FLAG = 
DLDFLAGS = $(ldflags) $(dldflags) $(ARCH_FLAG)
LDSHARED = $(CC) -dynamic -bundle
LDSHAREDXX = $(CXX) -dynamic -bundle
AR = libtool -static
EXEEXT = 

RUBY_INSTALL_NAME = $(RUBY_BASE_NAME)
RUBY_SO_NAME = ruby.2.6
RUBYW_INSTALL_NAME = 
RUBY_VERSION_NAME = $(RUBY_BASE_NAME)-$(ruby_version)
RUBYW_BASE_NAME = rubyw
RUBY_BASE_NAME = ruby

arch = x86_64-darwin19
sitearch = $(arch)
ruby_version = 2.6.0
ruby = $(bindir)/$(RUBY_BASE_NAME)
RUBY = $(ruby)
ruby_headers = $(hdrdir)/ruby.h $(hdrdir)/ruby/backward.h $(hdrdir)/ruby/ruby.h $(hdrdir)/ruby/defines.h $(hdrdir)/ruby/missing.h $(hdrdir)/ruby/intern.h $(hdrdir)/ruby/st.h $(hdrdir)/ruby/subst.h $(arch_hdrdir)/ruby/config.h

RM = rm -f
RM_RF = $(RUBY) -run -e rm -- -rf
RMDIRS = rmdir -p
MAKEDIRS = mkdir -p
INSTALL = /usr/bin/install -c
INSTALL_PROG = $(INSTALL) -m 0755
INSTALL_DATA = $(INSTALL) -m 644
COPY = cp
TOUCH = exit >

#### End of system configuration section. ####

preload = 
libpath = . $(libdir) /usr/local/opt/openssl/lib /usr/local/opt/readline/lib /usr/local/opt/libyaml/lib /usr/local/opt/gdbm/lib
LIBPATH =  -L. -L$(libdir) -L/usr/local/opt/openssl/lib -L/usr/local/opt/readline/lib -L/usr/local/opt/libyaml/lib -L/usr/local/opt/gdbm/lib
DEFFILE = 

CLEANFILES = mkmf.log
DISTCLEANFILES = 
DISTCLEANDIRS = 

extout = 
extout_prefix = 
target_prefix = /mysql2
LOCAL_LIBS = 
LIBS =  -L/usr/local/Cellar/mysql-client/5.7.10/lib -lmysqlclient -lssl -lcrypto   
ORIG_SRCS = client.c infile.c mysql2_ext.c result.c statement.c
SRCS = $(ORIG_SRCS) 
OBJS = client.o infile.o mysql2_ext.o result.o statement.o
HDRS = $(srcdir)/client.h $(srcdir)/mysql2_ext.h $(srcdir)/result.h $(srcdir)/statement.h $(srcdir)/mysql_enc_name_to_ruby.h $(srcdir)/mysql_enc_to_ruby.h $(srcdir)/wait_for_single_fd.h $(srcdir)/infile.h
LOCAL_HDRS = 
TARGET = mysql2
TARGET_NAME = mysql2
TARGET_ENTRY = Init_$(TARGET_NAME)
DLLIB = $(TARGET).bundle
EXTSTATIC = 
STATIC_LIB = 

TIMESTAMP_DIR = .
BINDIR        = $(bindir)
RUBYCOMMONDIR = $(sitedir)$(target_prefix)
RUBYLIBDIR    = $(sitelibdir)$(target_prefix)
RUBYARCHDIR   = $(sitearchdir)$(target_prefix)
HDRDIR        = $(rubyhdrdir)/ruby$(target_prefix)
ARCHHDRDIR    = $(rubyhdrdir)/$(arch)/ruby$(target_prefix)
TARGET_SO_DIR =
TARGET_SO     = $(TARGET_SO_DIR)$(DLLIB)
CLEANLIBS     = $(TARGET_SO) 
CLEANOBJS     = *.o  *.bak

all:    $(DLLIB)
static: $(STATIC_LIB)
.PHONY: all install static install-so install-rb
.PHONY: clean clean-so clean-static clean-rb

clean-static::
clean-rb-default::
clean-rb::
clean-so::
clean: clean-so clean-static clean-rb-default clean-rb
		-$(Q)$(RM) $(CLEANLIBS) $(CLEANOBJS) $(CLEANFILES) .*.time

distclean-rb-default::
distclean-rb::
distclean-so::
distclean-static::
distclean: clean distclean-so distclean-static distclean-rb-default distclean-rb
		-$(Q)$(RM) Makefile $(RUBY_EXTCONF_H) conftest.* mkmf.log
		-$(Q)$(RM) core ruby$(EXEEXT) *~ $(DISTCLEANFILES)
		-$(Q)$(RMDIRS) $(DISTCLEANDIRS) 2> /dev/null || true

realclean: distclean
install: install-so install-rb

install-so: $(DLLIB) $(TIMESTAMP_DIR)/.sitearchdir.-.mysql2.time
	$(INSTALL_PROG) $(DLLIB) $(RUBYARCHDIR)
clean-static::
	-$(Q)$(RM) $(STATIC_LIB)
install-rb: pre-install-rb do-install-rb install-rb-default
install-rb-default: pre-install-rb-default do-install-rb-default
pre-install-rb: Makefile
pre-install-rb-default: Makefile
do-install-rb:
do-install-rb-default:
pre-install-rb-default:
	@$(NULLCMD)
$(TIMESTAMP_DIR)/.sitearchdir.-.mysql2.time:
	$(Q) $(MAKEDIRS) $(@D) $(RUBYARCHDIR)
	$(Q) $(TOUCH) $@

site-install: site-install-so site-install-rb
site-install-so: install-so
site-install-rb: install-rb

.SUFFIXES: .c .m .cc .mm .cxx .cpp .o .S

.cc.o:
	$(ECHO) compiling $(<)
	$(Q) $(CXX) $(INCFLAGS) $(CPPFLAGS) $(CXXFLAGS) $(COUTFLAG)$@ -c $(CSRCFLAG)$<

.cc.S:
	$(ECHO) translating $(<)
	$(Q) $(CXX) $(INCFLAGS) $(CPPFLAGS) $(CXXFLAGS) $(COUTFLAG)$@ -S $(CSRCFLAG)$<

.mm.o:
	$(ECHO) compiling $(<)
	$(Q) $(CXX) $(INCFLAGS) $(CPPFLAGS) $(CXXFLAGS) $(COUTFLAG)$@ -c $(CSRCFLAG)$<

.mm.S:
	$(ECHO) translating $(<)
	$(Q) $(CXX) $(INCFLAGS) $(CPPFLAGS) $(CXXFLAGS) $(COUTFLAG)$@ -S $(CSRCFLAG)$<

.cxx.o:
	$(ECHO) compiling $(<)
	$(Q) $(CXX) $(INCFLAGS) $(CPPFLAGS) $(CXXFLAGS) $(COUTFLAG)$@ -c $(CSRCFLAG)$<

.cxx.S:
	$(ECHO) translating $(<)
	$(Q) $(CXX) $(INCFLAGS) $(CPPFLAGS) $(CXXFLAGS) $(COUTFLAG)$@ -S $(CSRCFLAG)$<

.cpp.o:
	$(ECHO) compiling $(<)
	$(Q) $(CXX) $(INCFLAGS) $(CPPFLAGS) $(CXXFLAGS) $(COUTFLAG)$@ -c $(CSRCFLAG)$<

.cpp.S:
	$(ECHO) translating $(<)
	$(Q) $(CXX) $(INCFLAGS) $(CPPFLAGS) $(CXXFLAGS) $(COUTFLAG)$@ -S $(CSRCFLAG)$<

.c.o:
	$(ECHO) compiling $(<)
	$(Q) $(CC) $(INCFLAGS) $(CPPFLAGS) $(CFLAGS) $(COUTFLAG)$@ -c $(CSRCFLAG)$<

.c.S:
	$(ECHO) translating $(<)
	$(Q) $(CC) $(INCFLAGS) $(CPPFLAGS) $(CFLAGS) $(COUTFLAG)$@ -S $(CSRCFLAG)$<

.m.o:
	$(ECHO) compiling $(<)
	$(Q) $(CC) $(INCFLAGS) $(CPPFLAGS) $(CFLAGS) $(COUTFLAG)$@ -c $(CSRCFLAG)$<

.m.S:
	$(ECHO) translating $(<)
	$(Q) $(CC) $(INCFLAGS) $(CPPFLAGS) $(CFLAGS) $(COUTFLAG)$@ -S $(CSRCFLAG)$<

$(TARGET_SO): $(OBJS) Makefile
	$(ECHO) linking shared-object mysql2/$(DLLIB)
	-$(Q)$(RM) $(@)
	$(Q) $(LDSHARED) -o $@ $(OBJS) $(LIBPATH) $(DLDFLAGS) $(LOCAL_LIBS) $(LIBS)
	$(Q) $(POSTLINK)



$(OBJS): $(HDRS) $(ruby_headers)

[eregon]

ldflags  = -L. -fstack-protector-strong -L/usr/local/lib -L/usr/local/opt/openssl/lib -L/usr/local/opt/readline/lib -L/usr/local/opt/libyaml/lib -L/usr/local/opt/gdbm/lib -Wl,-rpath,/usr/local/Cellar/mysql-client/5.7.10/lib
dldflags = -Wl,-undefined,dynamic_lookup -Wl,-multiply_defined,suppress -L/usr/local/opt/openssl/lib -L/usr/local/opt/readline/lib -L/usr/local/opt/libyaml/lib -L/usr/local/opt/gdbm/lib 

So these values seem to be provided at ./configure time to MRI with something like ./configure --with-openssl-dir=/usr/local/opt/openssl, in your case done by ruby-build:
https://github.com/rbenv/ruby-build/blob/da8e0b41fc93f84f4298d63efff15107332c064a/bin/ruby-build#L1023-L1031

Moral of the story: some C extensions expect to just inherit build-time settings for libraries MRI itself depends on like libssl.
We can likely add /usr/local/opt/openssl/lib in LDFLAGS on TruffleRuby to fix this.

[eregon]

@chrisseaton Could you also share ruby -e 'pp RbConfig::MAKEFILE_CONFIG' and ruby -e 'pp RbConfig::CONFIG' ? That should make it easier to pinpoint how this works in MRI.

[chrisseaton]

% ruby -e 'pp RbConfig::MAKEFILE_CONFIG'
{"DESTDIR"=>"",
 "MAJOR"=>"2",
 "MINOR"=>"6",
 "TEENY"=>"5",
 "PATCHLEVEL"=>"114",
 "INSTALL"=>"/usr/bin/install -c",
 "EXEEXT"=>"",
 "prefix"=>"/Users/chrisseaton/.rubies/ruby-2.6.5",
 "ruby_install_name"=>"$(RUBY_BASE_NAME)",
 "RUBY_INSTALL_NAME"=>"$(RUBY_BASE_NAME)",
 "RUBY_SO_NAME"=>"$(RUBY_BASE_NAME).$(RUBY_API_VERSION)",
 "exec"=>"exec",
 "ruby_pc"=>"ruby-2.6.pc",
 "CC_WRAPPER"=>"",
 "PACKAGE"=>"ruby",
 "BUILTIN_TRANSSRCS"=>" enc/trans/newline.c",
 "MANTYPE"=>"doc",
 "vendorarchhdrdir"=>"$(vendorhdrdir)/$(sitearch)",
 "sitearchhdrdir"=>"$(sitehdrdir)/$(sitearch)",
 "rubyarchhdrdir"=>"$(rubyhdrdir)/$(arch)",
 "vendorhdrdir"=>"$(rubyhdrdir)/vendor_ruby",
 "sitehdrdir"=>"$(rubyhdrdir)/site_ruby",
 "rubyhdrdir"=>"$(includedir)/$(RUBY_VERSION_NAME)",
 "RUBY_SEARCH_PATH"=>"",
 "UNIVERSAL_INTS"=>"",
 "UNIVERSAL_ARCHNAMES"=>"",
 "configure_args"=>
  " '--prefix=/Users/chrisseaton/.rubies/ruby-2.6.5' '--with-opt-dir=/usr/local/opt/openssl:/usr/local/opt/readline:/usr/local/opt/libyaml:/usr/local/opt/gdbm'",
 "CONFIGURE"=>"configure",
 "vendorarchdir"=>"$(vendorlibdir)/$(sitearch)",
 "vendorlibdir"=>"$(vendordir)/$(ruby_version)",
 "vendordir"=>"$(rubylibprefix)/vendor_ruby",
 "sitearchdir"=>"$(sitelibdir)/$(sitearch)",
 "sitelibdir"=>"$(sitedir)/$(ruby_version)",
 "sitedir"=>"$(rubylibprefix)/site_ruby",
 "rubyarchdir"=>"$(rubylibdir)/$(arch)",
 "rubylibdir"=>"$(rubylibprefix)/$(ruby_version)",
 "ruby_version"=>"2.6.0",
 "sitearch"=>"$(arch)",
 "arch"=>"x86_64-darwin19",
 "sitearchincludedir"=>"$(includedir)/$(sitearch)",
 "archincludedir"=>"$(includedir)/$(arch)",
 "sitearchlibdir"=>"$(libdir)/$(sitearch)",
 "archlibdir"=>"$(libdir)/$(arch)",
 "libdirname"=>"libdir",
 "RUBY_EXEC_PREFIX"=>"/Users/chrisseaton/.rubies/ruby-2.6.5",
 "RUBY_LIB_VERSION"=>"",
 "RUBY_LIB_VERSION_STYLE"=>"3\t/* full */",
 "RI_BASE_NAME"=>"ri",
 "ridir"=>"$(datarootdir)/$(RI_BASE_NAME)",
 "rubysitearchprefix"=>"$(rubylibprefix)/$(sitearch)",
 "rubyarchprefix"=>"$(rubylibprefix)/$(arch)",
 "MAKEFILES"=>"Makefile GNUmakefile",
 "PLATFORM_DIR"=>"",
 "THREAD_MODEL"=>"pthread",
 "SYMBOL_PREFIX"=>"_",
 "EXPORT_PREFIX"=>"",
 "COMMON_HEADERS"=>"",
 "COMMON_MACROS"=>"",
 "COMMON_LIBS"=>"",
 "MAINLIBS"=>"-lpthread -lgmp -ldl -lobjc",
 "ENABLE_SHARED"=>"no",
 "DLDSHARED"=>"$(CC) -dynamiclib",
 "DLDLIBS"=>"",
 "SOLIBS"=>"$(MAINLIBS)",
 "LIBRUBYARG_SHARED"=>"",
 "LIBRUBYARG_STATIC"=>
  "-l$(RUBY_SO_NAME)-static -framework Security -framework Foundation $(MAINLIBS)",
 "LIBRUBYARG"=>"$(LIBRUBYARG_STATIC)",
 "LIBRUBY"=>"$(LIBRUBY_A)",
 "LIBRUBY_ALIASES"=>"lib$(RUBY_SO_NAME).$(SOEXT)",
 "LIBRUBY_SONAME"=>"lib$(RUBY_SO_NAME).$(SOEXT).$(RUBY_API_VERSION)",
 "LIBRUBY_SO"=>"lib$(RUBY_SO_NAME).$(SOEXT).$(RUBY_PROGRAM_VERSION)",
 "LIBRUBY_A"=>"lib$(RUBY_SO_NAME)-static.a",
 "RUBYW_INSTALL_NAME"=>"",
 "rubyw_install_name"=>"",
 "EXTDLDFLAGS"=>"",
 "EXTLDFLAGS"=>"",
 "strict_warnflags"=>"",
 "warnflags"=>
  "-Wall -Wextra -Wdeclaration-after-statement -Wdeprecated-declarations -Wdivision-by-zero -Wimplicit-function-declaration -Wimplicit-int -Wpointer-arith -Wshorten-64-to-32 -Wwrite-strings -Wmissing-noreturn -Wno-constant-logical-operand -Wno-long-long -Wno-missing-field-initializers -Wno-overlength-strings -Wno-parentheses-equality -Wno-self-assign -Wno-tautological-compare -Wno-unused-parameter -Wno-unused-value -Wunused-variable -Wextra-tokens",
 "debugflags"=>"-ggdb3",
 "optflags"=>"-O3",
 "NULLCMD"=>":",
 "ENABLE_DEBUG_ENV"=>"",
 "DLNOBJ"=>"dln.o",
 "INSTALL_STATIC_LIBRARY"=>"yes",
 "MJIT_SUPPORT"=>"yes",
 "EXECUTABLE_EXTS"=>"",
 "ARCHFILE"=>"",
 "LIBRUBY_RELATIVE"=>"no",
 "EXTOUT"=>".ext",
 "PREP"=>"miniruby$(EXEEXT) exe/$(PROGRAM)",
 "CROSS_COMPILING"=>"no",
 "TEST_RUNNABLE"=>"yes",
 "rubylibprefix"=>"$(libdir)/$(RUBY_BASE_NAME)",
 "setup"=>"Setup",
 "ENCSTATIC"=>"",
 "EXTSTATIC"=>"",
 "STRIP"=>"strip -A -n",
 "SOEXT"=>"dylib",
 "TRY_LINK"=>"",
 "PRELOADENV"=>"DYLD_INSERT_LIBRARIES",
 "LIBPATHENV"=>"DYLD_FALLBACK_LIBRARY_PATH",
 "RPATHFLAG"=>"",
 "LIBPATHFLAG"=>" -L%s",
 "LINK_SO"=>"\n" + "$(POSTLINK)",
 "ASMEXT"=>"S",
 "LIBEXT"=>"a",
 "DLEXT2"=>"",
 "DLEXT"=>"bundle",
 "LDSHAREDXX"=>"$(CXX) -dynamic -bundle",
 "LDSHARED"=>"$(CC) -dynamic -bundle",
 "CCDLFLAGS"=>"-fno-common",
 "STATIC"=>"",
 "ARCH_FLAG"=>"",
 "DLDFLAGS"=>
  "-Wl,-undefined,dynamic_lookup -Wl,-multiply_defined,suppress -L/usr/local/opt/openssl/lib -L/usr/local/opt/readline/lib -L/usr/local/opt/libyaml/lib -L/usr/local/opt/gdbm/lib",
 "ALLOCA"=>"",
 "MATHN"=>"yes",
 "dsymutil"=>"dsymutil",
 "codesign"=>"codesign",
 "POSTLINK"=>
  "dsymutil $@; { test -z '$(RUBY_CODESIGN)' || codesign -s '$(RUBY_CODESIGN)' -f $@; }",
 "WERRORFLAG"=>"-Werror",
 "CHDIR"=>"cd -P",
 "RMALL"=>"rm -fr",
 "RMDIRS"=>"rmdir -p",
 "RMDIR"=>"rmdir",
 "CP"=>"cp",
 "RM"=>"rm -f",
 "PKG_CONFIG"=>"pkg-config",
 "DOXYGEN"=>"",
 "DOT"=>"dot",
 "MAKEDIRS"=>"mkdir -p",
 "MKDIR_P"=>"mkdir -p",
 "INSTALL_DATA"=>"$(INSTALL) -m 644",
 "INSTALL_SCRIPT"=>"$(INSTALL)",
 "INSTALL_PROGRAM"=>"$(INSTALL)",
 "SET_MAKE"=>"",
 "LN_S"=>"ln -s",
 "NM"=>"nm",
 "DLLWRAP"=>"",
 "WINDRES"=>"",
 "OBJCOPY"=>":",
 "OBJDUMP"=>"objdump",
 "ASFLAGS"=>"",
 "AS"=>"as",
 "ARFLAGS"=>"-no_warning_for_no_symbols -o ",
 "AR"=>"libtool -static",
 "RANLIB"=>":",
 "try_header"=>"",
 "CC_VERSION_MESSAGE"=>
  "Apple clang version 11.0.0 (clang-1100.0.33.8)\n" +
  "Target: x86_64-apple-darwin19.0.0\n" +
  "Thread model: posix\n" +
  "InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin",
 "CC_VERSION"=>"$(CC) --version",
 "CSRCFLAG"=>"",
 "COUTFLAG"=>"-o ",
 "OUTFLAG"=>"-o ",
 "CPPOUTFILE"=>"-o conftest.i",
 "GNU_LD"=>"no",
 "LD"=>"ld",
 "GCC"=>"yes",
 "EGREP"=>"/usr/bin/grep -E",
 "GREP"=>"/usr/bin/grep",
 "CPP"=>"$(CC) -E",
 "CXXFLAGS"=>"$(cxxflags)",
 "CXX"=>"clang++",
 "OBJEXT"=>"o",
 "CPPFLAGS"=>
  " -I/usr/local/opt/openssl/include -I/usr/local/opt/readline/include -I/usr/local/opt/libyaml/include -I/usr/local/opt/gdbm/include -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE -D_DARWIN_UNLIMITED_SELECT -D_REENTRANT $(DEFS) $(cppflags)",
 "LDFLAGS"=>
  "-L. -fstack-protector-strong -L/usr/local/lib -L/usr/local/opt/openssl/lib -L/usr/local/opt/readline/lib -L/usr/local/opt/libyaml/lib -L/usr/local/opt/gdbm/lib",
 "CFLAGS"=>"$(cflags)  -pipe",
 "CC"=>"clang",
 "target_os"=>"darwin19",
 "target_vendor"=>"apple",
 "target_cpu"=>"x86_64",
 "target"=>"x86_64-apple-darwin19",
 "host_os"=>"darwin19.0.0",
 "host_vendor"=>"apple",
 "host_cpu"=>"x86_64",
 "host"=>"x86_64-apple-darwin19.0.0",
 "RUBY_VERSION_NAME"=>"$(RUBY_BASE_NAME)-$(ruby_version)",
 "RUBYW_BASE_NAME"=>"rubyw",
 "RUBY_BASE_NAME"=>"ruby",
 "build_os"=>"darwin19.0.0",
 "build_vendor"=>"apple",
 "build_cpu"=>"x86_64",
 "build"=>"x86_64-apple-darwin19.0.0",
 "RUBY_API_VERSION"=>"$(MAJOR).$(MINOR)",
 "RUBY_PROGRAM_VERSION"=>"2.6.5",
 "HAVE_GIT"=>"yes",
 "GIT"=>"git",
 "cxxflags"=>"$(optflags) $(debugflags) $(warnflags)",
 "cppflags"=>"",
 "cflags"=>"$(optflags) $(debugflags) $(warnflags)",
 "target_alias"=>"",
 "host_alias"=>"",
 "build_alias"=>"",
 "LIBS"=>"",
 "ECHO_T"=>"",
 "ECHO_N"=>"",
 "ECHO_C"=>"\\\\c",
 "DEFS"=>"",
 "mandir"=>"$(datarootdir)/man",
 "localedir"=>"$(datarootdir)/locale",
 "libdir"=>"$(exec_prefix)/lib",
 "psdir"=>"$(docdir)",
 "pdfdir"=>"$(docdir)",
 "dvidir"=>"$(docdir)",
 "htmldir"=>"$(docdir)",
 "infodir"=>"$(datarootdir)/info",
 "docdir"=>"$(datarootdir)/doc/$(PACKAGE)",
 "oldincludedir"=>"$(SDKROOT)/usr/include",
 "includedir"=>"$(prefix)/include",
 "runstatedir"=>"$(localstatedir)/run",
 "localstatedir"=>"$(prefix)/var",
 "sharedstatedir"=>"$(prefix)/com",
 "sysconfdir"=>"$(prefix)/etc",
 "datadir"=>"$(datarootdir)",
 "datarootdir"=>"$(prefix)/share",
 "libexecdir"=>"$(exec_prefix)/libexec",
 "sbindir"=>"$(exec_prefix)/sbin",
 "bindir"=>"$(exec_prefix)/bin",
 "exec_prefix"=>"$(prefix)",
 "PACKAGE_URL"=>"",
 "PACKAGE_BUGREPORT"=>"",
 "PACKAGE_STRING"=>"",
 "PACKAGE_VERSION"=>"",
 "PACKAGE_TARNAME"=>"",
 "PACKAGE_NAME"=>"",
 "PATH_SEPARATOR"=>":",
 "SHELL"=>"/bin/sh",
 "UNICODE_VERSION"=>"12.1.0",
 "UNICODE_EMOJI_VERSION"=>"12.0",
 "SDKROOT"=>"",
 "archdir"=>"$(rubyarchdir)",
 "topdir"=>
  "/Users/chrisseaton/.rubies/ruby-2.6.5/lib/ruby/2.6.0/x86_64-darwin19"}

% ruby -e 'pp RbConfig::CONFIG'
{"DESTDIR"=>"",
 "MAJOR"=>"2",
 "MINOR"=>"6",
 "TEENY"=>"5",
 "PATCHLEVEL"=>"114",
 "INSTALL"=>"/usr/bin/install -c",
 "EXEEXT"=>"",
 "prefix"=>"/Users/chrisseaton/.rubies/ruby-2.6.5",
 "ruby_install_name"=>"ruby",
 "RUBY_INSTALL_NAME"=>"ruby",
 "RUBY_SO_NAME"=>"ruby.2.6",
 "exec"=>"exec",
 "ruby_pc"=>"ruby-2.6.pc",
 "CC_WRAPPER"=>"",
 "PACKAGE"=>"ruby",
 "BUILTIN_TRANSSRCS"=>" enc/trans/newline.c",
 "MANTYPE"=>"doc",
 "vendorarchhdrdir"=>
  "/Users/chrisseaton/.rubies/ruby-2.6.5/include/ruby-2.6.0/vendor_ruby/x86_64-darwin19",
 "sitearchhdrdir"=>
  "/Users/chrisseaton/.rubies/ruby-2.6.5/include/ruby-2.6.0/site_ruby/x86_64-darwin19",
 "rubyarchhdrdir"=>
  "/Users/chrisseaton/.rubies/ruby-2.6.5/include/ruby-2.6.0/x86_64-darwin19",
 "vendorhdrdir"=>
  "/Users/chrisseaton/.rubies/ruby-2.6.5/include/ruby-2.6.0/vendor_ruby",
 "sitehdrdir"=>
  "/Users/chrisseaton/.rubies/ruby-2.6.5/include/ruby-2.6.0/site_ruby",
 "rubyhdrdir"=>"/Users/chrisseaton/.rubies/ruby-2.6.5/include/ruby-2.6.0",
 "RUBY_SEARCH_PATH"=>"",
 "UNIVERSAL_INTS"=>"",
 "UNIVERSAL_ARCHNAMES"=>"",
 "configure_args"=>
  " '--prefix=/Users/chrisseaton/.rubies/ruby-2.6.5' '--with-opt-dir=/usr/local/opt/openssl:/usr/local/opt/readline:/usr/local/opt/libyaml:/usr/local/opt/gdbm'",
 "CONFIGURE"=>"configure",
 "vendorarchdir"=>
  "/Users/chrisseaton/.rubies/ruby-2.6.5/lib/ruby/vendor_ruby/2.6.0/x86_64-darwin19",
 "vendorlibdir"=>
  "/Users/chrisseaton/.rubies/ruby-2.6.5/lib/ruby/vendor_ruby/2.6.0",
 "vendordir"=>"/Users/chrisseaton/.rubies/ruby-2.6.5/lib/ruby/vendor_ruby",
 "sitearchdir"=>
  "/Users/chrisseaton/.rubies/ruby-2.6.5/lib/ruby/site_ruby/2.6.0/x86_64-darwin19",
 "sitelibdir"=>
  "/Users/chrisseaton/.rubies/ruby-2.6.5/lib/ruby/site_ruby/2.6.0",
 "sitedir"=>"/Users/chrisseaton/.rubies/ruby-2.6.5/lib/ruby/site_ruby",
 "rubyarchdir"=>
  "/Users/chrisseaton/.rubies/ruby-2.6.5/lib/ruby/2.6.0/x86_64-darwin19",
 "rubylibdir"=>"/Users/chrisseaton/.rubies/ruby-2.6.5/lib/ruby/2.6.0",
 "ruby_version"=>"2.6.0",
 "sitearch"=>"x86_64-darwin19",
 "arch"=>"x86_64-darwin19",
 "sitearchincludedir"=>
  "/Users/chrisseaton/.rubies/ruby-2.6.5/include/x86_64-darwin19",
 "archincludedir"=>
  "/Users/chrisseaton/.rubies/ruby-2.6.5/include/x86_64-darwin19",
 "sitearchlibdir"=>"/Users/chrisseaton/.rubies/ruby-2.6.5/lib/x86_64-darwin19",
 "archlibdir"=>"/Users/chrisseaton/.rubies/ruby-2.6.5/lib/x86_64-darwin19",
 "libdirname"=>"libdir",
 "RUBY_EXEC_PREFIX"=>"/Users/chrisseaton/.rubies/ruby-2.6.5",
 "RUBY_LIB_VERSION"=>"",
 "RUBY_LIB_VERSION_STYLE"=>"3\t/* full */",
 "RI_BASE_NAME"=>"ri",
 "ridir"=>"/Users/chrisseaton/.rubies/ruby-2.6.5/share/ri",
 "rubysitearchprefix"=>
  "/Users/chrisseaton/.rubies/ruby-2.6.5/lib/ruby/x86_64-darwin19",
 "rubyarchprefix"=>
  "/Users/chrisseaton/.rubies/ruby-2.6.5/lib/ruby/x86_64-darwin19",
 "MAKEFILES"=>"Makefile GNUmakefile",
 "PLATFORM_DIR"=>"",
 "THREAD_MODEL"=>"pthread",
 "SYMBOL_PREFIX"=>"_",
 "EXPORT_PREFIX"=>"",
 "COMMON_HEADERS"=>"",
 "COMMON_MACROS"=>"",
 "COMMON_LIBS"=>"",
 "MAINLIBS"=>"-lpthread -lgmp -ldl -lobjc",
 "ENABLE_SHARED"=>"no",
 "DLDSHARED"=>"clang -dynamiclib",
 "DLDLIBS"=>"",
 "SOLIBS"=>"-lpthread -lgmp -ldl -lobjc",
 "LIBRUBYARG_SHARED"=>"",
 "LIBRUBYARG_STATIC"=>
  "-lruby.2.6-static -framework Security -framework Foundation -lpthread -lgmp -ldl -lobjc",
 "LIBRUBYARG"=>
  "-lruby.2.6-static -framework Security -framework Foundation -lpthread -lgmp -ldl -lobjc",
 "LIBRUBY"=>"libruby.2.6-static.a",
 "LIBRUBY_ALIASES"=>"libruby.2.6.dylib",
 "LIBRUBY_SONAME"=>"libruby.2.6.dylib.2.6",
 "LIBRUBY_SO"=>"libruby.2.6.dylib.2.6.5",
 "LIBRUBY_A"=>"libruby.2.6-static.a",
 "RUBYW_INSTALL_NAME"=>"",
 "rubyw_install_name"=>"",
 "EXTDLDFLAGS"=>"",
 "EXTLDFLAGS"=>"",
 "strict_warnflags"=>"",
 "warnflags"=>
  "-Wall -Wextra -Wdeclaration-after-statement -Wdeprecated-declarations -Wdivision-by-zero -Wimplicit-function-declaration -Wimplicit-int -Wpointer-arith -Wshorten-64-to-32 -Wwrite-strings -Wmissing-noreturn -Wno-constant-logical-operand -Wno-long-long -Wno-missing-field-initializers -Wno-overlength-strings -Wno-parentheses-equality -Wno-self-assign -Wno-tautological-compare -Wno-unused-parameter -Wno-unused-value -Wunused-variable -Wextra-tokens",
 "debugflags"=>"-ggdb3",
 "optflags"=>"-O3",
 "NULLCMD"=>":",
 "ENABLE_DEBUG_ENV"=>"",
 "DLNOBJ"=>"dln.o",
 "INSTALL_STATIC_LIBRARY"=>"yes",
 "MJIT_SUPPORT"=>"yes",
 "EXECUTABLE_EXTS"=>"",
 "ARCHFILE"=>"",
 "LIBRUBY_RELATIVE"=>"no",
 "EXTOUT"=>".ext",
 "PREP"=>"miniruby exe/$(PROGRAM)",
 "CROSS_COMPILING"=>"no",
 "TEST_RUNNABLE"=>"yes",
 "rubylibprefix"=>"/Users/chrisseaton/.rubies/ruby-2.6.5/lib/ruby",
 "setup"=>"Setup",
 "ENCSTATIC"=>"",
 "EXTSTATIC"=>"",
 "STRIP"=>"strip -A -n",
 "SOEXT"=>"dylib",
 "TRY_LINK"=>"",
 "PRELOADENV"=>"DYLD_INSERT_LIBRARIES",
 "LIBPATHENV"=>"DYLD_FALLBACK_LIBRARY_PATH",
 "RPATHFLAG"=>"",
 "LIBPATHFLAG"=>" -L%s",
 "LINK_SO"=>
  "\n" +
  "dsymutil $@; { test -z '$(RUBY_CODESIGN)' || codesign -s '$(RUBY_CODESIGN)' -f $@; }",
 "ASMEXT"=>"S",
 "LIBEXT"=>"a",
 "DLEXT2"=>"",
 "DLEXT"=>"bundle",
 "LDSHAREDXX"=>"clang++ -dynamic -bundle",
 "LDSHARED"=>"clang -dynamic -bundle",
 "CCDLFLAGS"=>"-fno-common",
 "STATIC"=>"",
 "ARCH_FLAG"=>"",
 "DLDFLAGS"=>
  "-Wl,-undefined,dynamic_lookup -Wl,-multiply_defined,suppress -L/usr/local/opt/openssl/lib -L/usr/local/opt/readline/lib -L/usr/local/opt/libyaml/lib -L/usr/local/opt/gdbm/lib",
 "ALLOCA"=>"",
 "MATHN"=>"yes",
 "dsymutil"=>"dsymutil",
 "codesign"=>"codesign",
 "POSTLINK"=>
  "dsymutil $@; { test -z '$(RUBY_CODESIGN)' || codesign -s '$(RUBY_CODESIGN)' -f $@; }",
 "WERRORFLAG"=>"-Werror",
 "CHDIR"=>"cd -P",
 "RMALL"=>"rm -fr",
 "RMDIRS"=>"rmdir -p",
 "RMDIR"=>"rmdir",
 "CP"=>"cp",
 "RM"=>"rm -f",
 "PKG_CONFIG"=>"pkg-config",
 "DOXYGEN"=>"",
 "DOT"=>"dot",
 "MAKEDIRS"=>"mkdir -p",
 "MKDIR_P"=>"mkdir -p",
 "INSTALL_DATA"=>"/usr/bin/install -c -m 644",
 "INSTALL_SCRIPT"=>"/usr/bin/install -c",
 "INSTALL_PROGRAM"=>"/usr/bin/install -c",
 "SET_MAKE"=>"",
 "LN_S"=>"ln -s",
 "NM"=>"nm",
 "DLLWRAP"=>"",
 "WINDRES"=>"",
 "OBJCOPY"=>":",
 "OBJDUMP"=>"objdump",
 "ASFLAGS"=>"",
 "AS"=>"as",
 "ARFLAGS"=>"-no_warning_for_no_symbols -o ",
 "AR"=>"libtool -static",
 "RANLIB"=>":",
 "try_header"=>"",
 "CC_VERSION_MESSAGE"=>
  "Apple clang version 11.0.0 (clang-1100.0.33.8)\n" +
  "Target: x86_64-apple-darwin19.0.0\n" +
  "Thread model: posix\n" +
  "InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin",
 "CC_VERSION"=>"clang --version",
 "CSRCFLAG"=>"",
 "COUTFLAG"=>"-o ",
 "OUTFLAG"=>"-o ",
 "CPPOUTFILE"=>"-o conftest.i",
 "GNU_LD"=>"no",
 "LD"=>"ld",
 "GCC"=>"yes",
 "EGREP"=>"/usr/bin/grep -E",
 "GREP"=>"/usr/bin/grep",
 "CPP"=>"clang -E",
 "CXXFLAGS"=>
  "-O3 -ggdb3 -Wall -Wextra -Wdeclaration-after-statement -Wdeprecated-declarations -Wdivision-by-zero -Wimplicit-function-declaration -Wimplicit-int -Wpointer-arith -Wshorten-64-to-32 -Wwrite-strings -Wmissing-noreturn -Wno-constant-logical-operand -Wno-long-long -Wno-missing-field-initializers -Wno-overlength-strings -Wno-parentheses-equality -Wno-self-assign -Wno-tautological-compare -Wno-unused-parameter -Wno-unused-value -Wunused-variable -Wextra-tokens",
 "CXX"=>"clang++",
 "OBJEXT"=>"o",
 "CPPFLAGS"=>
  " -I/usr/local/opt/openssl/include -I/usr/local/opt/readline/include -I/usr/local/opt/libyaml/include -I/usr/local/opt/gdbm/include -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE -D_DARWIN_UNLIMITED_SELECT -D_REENTRANT  ",
 "LDFLAGS"=>
  "-L. -fstack-protector-strong -L/usr/local/lib -L/usr/local/opt/openssl/lib -L/usr/local/opt/readline/lib -L/usr/local/opt/libyaml/lib -L/usr/local/opt/gdbm/lib",
 "CFLAGS"=>
  "-O3 -ggdb3 -Wall -Wextra -Wdeclaration-after-statement -Wdeprecated-declarations -Wdivision-by-zero -Wimplicit-function-declaration -Wimplicit-int -Wpointer-arith -Wshorten-64-to-32 -Wwrite-strings -Wmissing-noreturn -Wno-constant-logical-operand -Wno-long-long -Wno-missing-field-initializers -Wno-overlength-strings -Wno-parentheses-equality -Wno-self-assign -Wno-tautological-compare -Wno-unused-parameter -Wno-unused-value -Wunused-variable -Wextra-tokens  -pipe",
 "CC"=>"clang",
 "target_os"=>"darwin19",
 "target_vendor"=>"apple",
 "target_cpu"=>"x86_64",
 "target"=>"x86_64-apple-darwin19",
 "host_os"=>"darwin19.0.0",
 "host_vendor"=>"apple",
 "host_cpu"=>"x86_64",
 "host"=>"x86_64-apple-darwin19.0.0",
 "RUBY_VERSION_NAME"=>"ruby-2.6.0",
 "RUBYW_BASE_NAME"=>"rubyw",
 "RUBY_BASE_NAME"=>"ruby",
 "build_os"=>"darwin19.0.0",
 "build_vendor"=>"apple",
 "build_cpu"=>"x86_64",
 "build"=>"x86_64-apple-darwin19.0.0",
 "RUBY_API_VERSION"=>"2.6",
 "RUBY_PROGRAM_VERSION"=>"2.6.5",
 "HAVE_GIT"=>"yes",
 "GIT"=>"git",
 "cxxflags"=>
  "-O3 -ggdb3 -Wall -Wextra -Wdeclaration-after-statement -Wdeprecated-declarations -Wdivision-by-zero -Wimplicit-function-declaration -Wimplicit-int -Wpointer-arith -Wshorten-64-to-32 -Wwrite-strings -Wmissing-noreturn -Wno-constant-logical-operand -Wno-long-long -Wno-missing-field-initializers -Wno-overlength-strings -Wno-parentheses-equality -Wno-self-assign -Wno-tautological-compare -Wno-unused-parameter -Wno-unused-value -Wunused-variable -Wextra-tokens",
 "cppflags"=>"",
 "cflags"=>
  "-O3 -ggdb3 -Wall -Wextra -Wdeclaration-after-statement -Wdeprecated-declarations -Wdivision-by-zero -Wimplicit-function-declaration -Wimplicit-int -Wpointer-arith -Wshorten-64-to-32 -Wwrite-strings -Wmissing-noreturn -Wno-constant-logical-operand -Wno-long-long -Wno-missing-field-initializers -Wno-overlength-strings -Wno-parentheses-equality -Wno-self-assign -Wno-tautological-compare -Wno-unused-parameter -Wno-unused-value -Wunused-variable -Wextra-tokens",
 "target_alias"=>"",
 "host_alias"=>"",
 "build_alias"=>"",
 "LIBS"=>"",
 "ECHO_T"=>"",
 "ECHO_N"=>"",
 "ECHO_C"=>"\\\\c",
 "DEFS"=>"",
 "mandir"=>"/Users/chrisseaton/.rubies/ruby-2.6.5/share/man",
 "localedir"=>"/Users/chrisseaton/.rubies/ruby-2.6.5/share/locale",
 "libdir"=>"/Users/chrisseaton/.rubies/ruby-2.6.5/lib",
 "psdir"=>"/Users/chrisseaton/.rubies/ruby-2.6.5/share/doc/ruby",
 "pdfdir"=>"/Users/chrisseaton/.rubies/ruby-2.6.5/share/doc/ruby",
 "dvidir"=>"/Users/chrisseaton/.rubies/ruby-2.6.5/share/doc/ruby",
 "htmldir"=>"/Users/chrisseaton/.rubies/ruby-2.6.5/share/doc/ruby",
 "infodir"=>"/Users/chrisseaton/.rubies/ruby-2.6.5/share/info",
 "docdir"=>"/Users/chrisseaton/.rubies/ruby-2.6.5/share/doc/ruby",
 "oldincludedir"=>"/usr/include",
 "includedir"=>"/Users/chrisseaton/.rubies/ruby-2.6.5/include",
 "runstatedir"=>"/Users/chrisseaton/.rubies/ruby-2.6.5/var/run",
 "localstatedir"=>"/Users/chrisseaton/.rubies/ruby-2.6.5/var",
 "sharedstatedir"=>"/Users/chrisseaton/.rubies/ruby-2.6.5/com",
 "sysconfdir"=>"/Users/chrisseaton/.rubies/ruby-2.6.5/etc",
 "datadir"=>"/Users/chrisseaton/.rubies/ruby-2.6.5/share",
 "datarootdir"=>"/Users/chrisseaton/.rubies/ruby-2.6.5/share",
 "libexecdir"=>"/Users/chrisseaton/.rubies/ruby-2.6.5/libexec",
 "sbindir"=>"/Users/chrisseaton/.rubies/ruby-2.6.5/sbin",
 "bindir"=>"/Users/chrisseaton/.rubies/ruby-2.6.5/bin",
 "exec_prefix"=>"/Users/chrisseaton/.rubies/ruby-2.6.5",
 "PACKAGE_URL"=>"",
 "PACKAGE_BUGREPORT"=>"",
 "PACKAGE_STRING"=>"",
 "PACKAGE_VERSION"=>"",
 "PACKAGE_TARNAME"=>"",
 "PACKAGE_NAME"=>"",
 "PATH_SEPARATOR"=>":",
 "SHELL"=>"/bin/sh",
 "UNICODE_VERSION"=>"12.1.0",
 "UNICODE_EMOJI_VERSION"=>"12.0",
 "SDKROOT"=>"",
 "archdir"=>
  "/Users/chrisseaton/.rubies/ruby-2.6.5/lib/ruby/2.6.0/x86_64-darwin19",
 "topdir"=>
  "/Users/chrisseaton/.rubies/ruby-2.6.5/lib/ruby/2.6.0/x86_64-darwin19"}

[eregon]

Actually that's a Homebrew-installed MRI, it's not installed by ruby-build.
Here is the logic setting --with-opt-dir=:
https://github.com/Homebrew/homebrew-core/blob/29c7cfb92c0efed7fdb303f069bb3d2830fed636/Formula/ruby.rb#L47-L54

[eregon]

Fixed in 3541dce, thanks for the report and the help debugging this.