Nokogiri 1.6.8 Install Fails on Mac OS X with xz installed from Homebrew

[halostatue]

Action:

brew install xz
gem install nokogiri -v 1.6.8

Expected:

Nokogiri 1.6.8 installs correctly.

Actual:

Restoring gems to pristine condition...
Building native extensions.  This could take a while...
ERROR:  While executing gem ... (Gem::Ext::BuildError)
    ERROR: Failed to build gem native extension.

    current directory: /Users/austin/.gem/ruby/2.3.0/gems/nokogiri-1.6.8/ext/nokogiri
/Users/austin/.rubies/ruby-2.3.0/bin/ruby -r ./siteconf20160607-71935-1m9be2b.rb extconf.rb
Using pkg-config version 1.1.7
checking if the C compiler accepts ... yes
checking if the C compiler accepts -Wno-error=unused-command-line-argument-hard-error-in-future... no
Building nokogiri using packaged libraries.
Using mini_portile version 2.1.0
checking for iconv.h... yes
checking for gzdopen() in -lz... yes
checking for iconv... yes
************************************************************************
IMPORTANT NOTICE:

Building Nokogiri with a packaged version of libxml2-2.9.4.

Team Nokogiri will keep on doing their best to provide security
updates in a timely manner, but if this is a concern for you and want
to use the system library instead; abort this installation process and
reinstall nokogiri as follows:

    gem install nokogiri -- --use-system-libraries
        [--with-xml2-config=/path/to/xml2-config]
        [--with-xslt-config=/path/to/xslt-config]

If you are using Bundler, tell it to use the option:

    bundle config build.nokogiri --use-system-libraries
    bundle install

Note, however, that nokogiri is not fully compatible with arbitrary
versions of libxml2 provided by OS/package vendors.
************************************************************************
Extracting libxml2-2.9.4.tar.gz into tmp/x86_64-apple-darwin15.3.0/ports/libxml2/2.9.4... OK
Running 'configure' for libxml2 2.9.4... OK
Running 'compile' for libxml2 2.9.4... ERROR, review '/Users/austin/.gem/ruby/2.3.0/gems/nokogiri-1.6.8/ext/nokogiri/tmp/x86_64-apple-darwin15.3.0/ports/libxml2/2.9.4/compile.log' to see what happened. Last lines are:
========================================================================
    unsigned short* in = (unsigned short*) inb;
                         ^~~~~~~~~~~~~~~~~~~~~
encoding.c:815:27: warning: cast from 'unsigned char *' to 'unsigned short *' increases required alignment from 1 to 2 [-Wcast-align]
    unsigned short* out = (unsigned short*) outb;
                          ^~~~~~~~~~~~~~~~~~~~~~
4 warnings generated.
  CC       error.lo
  CC       parserInternals.lo
  CC       parser.lo
  CC       tree.lo
  CC       hash.lo
  CC       list.lo
  CC       xmlIO.lo
xmlIO.c:1450:52: error: use of undeclared identifier 'LZMA_OK'
    ret =  (__libxml2_xzclose((xzFile) context) == LZMA_OK ) ? 0 : -1;
                                                   ^
1 error generated.
make[2]: *** [xmlIO.lo] Error 1
make[1]: *** [all-recursive] Error 1
make: *** [all] Error 2
========================================================================
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of necessary
libraries and/or headers.  Check the mkmf.log file for more details.  You may
need configuration options.

Provided configuration options:
    --with-opt-dir
    --without-opt-dir
    --with-opt-include
    --without-opt-include=${opt-dir}/include
    --with-opt-lib
    --without-opt-lib=${opt-dir}/lib
    --with-make-prog
    --without-make-prog
    --srcdir=.
    --curdir
    --ruby=/Users/austin/.rubies/ruby-2.3.0/bin/$(RUBY_BASE_NAME)
    --help
    --clean
    --use-system-libraries
    --enable-static
    --disable-static
    --with-zlib-dir
    --without-zlib-dir
    --with-zlib-include
    --without-zlib-include=${zlib-dir}/include
    --with-zlib-lib
    --without-zlib-lib=${zlib-dir}/lib
    --enable-cross-build
    --disable-cross-build
/Users/austin/.gem/ruby/2.3.0/gems/mini_portile2-2.1.0/lib/mini_portile2/mini_portile.rb:366:in `block in execute': Failed to complete compile task (RuntimeError)
    from /Users/austin/.gem/ruby/2.3.0/gems/mini_portile2-2.1.0/lib/mini_portile2/mini_portile.rb:337:in `chdir'
    from /Users/austin/.gem/ruby/2.3.0/gems/mini_portile2-2.1.0/lib/mini_portile2/mini_portile.rb:337:in `execute'
    from /Users/austin/.gem/ruby/2.3.0/gems/mini_portile2-2.1.0/lib/mini_portile2/mini_portile.rb:111:in `compile'
    from /Users/austin/.gem/ruby/2.3.0/gems/mini_portile2-2.1.0/lib/mini_portile2/mini_portile.rb:150:in `cook'
    from extconf.rb:364:in `block (2 levels) in process_recipe'
    from extconf.rb:257:in `block in chdir_for_build'
    from extconf.rb:256:in `chdir'
    from extconf.rb:256:in `chdir_for_build'
    from extconf.rb:363:in `block in process_recipe'
    from extconf.rb:262:in `tap'
    from extconf.rb:262:in `process_recipe'
    from extconf.rb:555:in `<main>'

To see why this extension failed to compile, please check the mkmf.log which can be found here:

  /Users/austin/.gem/ruby/2.3.0/extensions/x86_64-darwin-15/2.3.0-static/nokogiri-1.6.8/mkmf.log

extconf failed, exit code 1

Gem files will remain installed in /Users/austin/.gem/ruby/2.3.0/gems/nokogiri-1.6.8 for inspection.
Results logged to /Users/austin/.gem/ruby/2.3.0/extensions/x86_64-darwin-15/2.3.0-static/nokogiri-1.6.8/gem_make.out
gem pristine nokogiri -v 1.6.8  9.23s user 7.56s system 92% cpu 18.089 total

When I do:

brew uninstall xz
gem install nokogiri -v 1.6.8

Nokogiri 1.6.8 installs correctly.

[kenaniah]

I had the same build failure. brew uninstall xz indeed allows nokogiri to compile.

[md5]

Although the brew uninstall xz workaround did work for me, I also ran across #1445, which has the same compilation error. It turns out that running xcode-select --install also worked for me, though I could have sworn I had already run that months ago.

[flavorjones]

summoning @aramprice

[aramprice]

tl;dr => xz installs a version of liblzma which can not be linked against when building nokogiri dependencies

Here's the info I've been able to dig up when running into this issue; resolved with the similar brew uninstall xz dance.

Looking in the .../nokogiri-1.6.8/mkmf.log there is the following message (in my case not at the end of the file):

ld: warning: ignoring file /usr/local/lib/liblzma.dylib, file was built for x86_64 which is not the architecture being linked (i386): /usr/local/lib/liblzma.dylib

It turns out that that /usr/local/lib/liblzma.dylib is part of the brew xz formulae:

brew info liblzma
lzma is now part of the xz formula.

Uninstalling allows the libxml compile to succeed. The unfortunate thing is that xz is a (recommended) dependency of ag (the_silver_searcher) so most people end up with it.

> brew info ag
the_silver_searcher: stable 0.32.0 (bottled), HEAD
Code-search similar to ack
https://github.com/ggreer/the_silver_searcher
Not installed
From: https://github.com/Homebrew/homebrew-core/blob/master/Formula/the_silver_searcher.rb
==> Dependencies
Build: autoconf ✘, automake ✘, pkg-config ✘
Required: pcre ✘
Recommended: xz ✘
==> Options
--without-xz
    Build without xz support
--HEAD
    Install HEAD version

Configuration:

• osx: Darwin 15.5.0 Darwin Kernel Version 15.5.0: Tue Apr 19 18:36:36 PDT 2016; root:xnu-3248.50.21~8/RELEASE_X86_64 x86_64
• ruby (system) ruby 2.0.0p648 (2015-12-16 revision 53162) [universal.x86_64-darwin15]

[DomT4]

ld: warning: ignoring file /usr/local/lib/liblzma.dylib, file was built for x86_64 which is not the architecture being linked (i386): /usr/local/lib/liblzma.dylib

This sounds like you want to nudge people to brew install xz --universal. I'm unable to reproduce this specific example locally though with a vanilla brew install xz in /usr/local and gem 2.5.1, ruby 2.3.1p112.

************************************************************************
Extracting libxslt-1.1.29.tar.gz into tmp/x86_64-apple-darwin15.5.0/ports/libxslt/1.1.29... OK
Running 'configure' for libxslt 1.1.29... OK
Running 'compile' for libxslt 1.1.29... OK
Running 'install' for libxslt 1.1.29... OK
Activating libxslt 1.1.29 (from /usr/local/var/rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/nokogiri-1.6.8/ports/x86_64-apple-darwin15.5.0/libxslt/1.1.29)...
checking for main() in -llzma... yes
checking for xmlParseDoc() in libxml/parser.h... yes
checking for xsltParseStylesheetDoc() in libxslt/xslt.h... yes
checking for exsltFuncRegister() in libexslt/exslt.h... yes
checking for xmlHasFeature()... yes
checking for xmlFirstElementChild()... yes
checking for xmlRelaxNGSetParserStructuredErrors()... yes
checking for xmlRelaxNGSetParserStructuredErrors()... yes
checking for xmlRelaxNGSetValidStructuredErrors()... yes
checking for xmlSchemaSetValidStructuredErrors()... yes
checking for xmlSchemaSetParserStructuredErrors()... yes
creating Makefile

[aramprice]

@DomT4 installing with --universal seemed to resolve the issue for me.

I also tried --without-xz which resulted in another "incompatible architecture" error for an iconv check

[DomT4]

which resulted in another "incompatible architecture" error for an iconv check

That's a bit odd. Anything in brew doctor or brew list | grep iconv?

[aramprice]

No problems reported by brew doctor and nothing listed for iconv.

The actual culprit is probably further back in the mkmf.log. I'll try to reproduce the error from having ag installed --without-xz and post them.

[jonbcampos]

If it helps anyone, I was able to get it build properly after a brew uninstall xz without having to do the recommended brew uinstall -force xz thus leaving xz 5.2.1 still on the computer. I don't know if this is good or bad though.

[aramprice]

Duplicated with on the following configuration:

→ uname -a
Darwin HOSTNAME 15.5.0 Darwin Kernel Version 15.5.0: Tue Apr 19 18:36:36 PDT 2016; root:xnu-3248.50.21~8/RELEASE_X86_64 x86_64

→ /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/bin/ruby -v
ruby 2.0.0p648 (2015-12-16 revision 53162) [universal.x86_64-darwin15]
  Gem::VERSION => 2.6.4
  Bundler::VERSION => 1.12.5

→ brew -v
Homebrew 0.9.9 (git revision 11d4; last commit 2016-06-08)
Homebrew/homebrew-core (git revision 2343; last commit 2016-06-10)

→ brew info xz
xz: stable 5.2.2 (bottled)
General-purpose data compression with high compression ratio
http://tukaani.org/xz/
/usr/local/Cellar/xz/5.2.2 (91 files, 1.4M) *
  Poured from bottle on 2016-06-10 at 14:45:50
From: https://github.com/Homebrew/homebrew-core/blob/master/Formula/xz.rb
==> Options
--universal
    Build a universal binary

→ xcode-select -p
/Library/Developer/CommandLineTools

Output from bundle:

Installing nokogiri 1.6.8 with native extensions

Gem::Ext::BuildError: ERROR: Failed to build gem native extension.

    current directory: tmp/ruby/2.0.0/gems/nokogiri-1.6.8/ext/nokogiri
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/bin/ruby -r ./siteconf20160610-69863-1yfw0mn.rb extconf.rb
Using pkg-config version 1.1.7
checking if the C compiler accepts ... yes
checking if the C compiler accepts -Wno-error=unused-command-line-argument-hard-error-in-future... no
Building nokogiri using packaged libraries.
Using mini_portile version 2.1.0
checking for iconv.h... yes
checking for gzdopen() in -lz... yes
checking for iconv... yes
************************************************************************
IMPORTANT NOTICE:

Building Nokogiri with a packaged version of libxml2-2.9.4.

Team Nokogiri will keep on doing their best to provide security
updates in a timely manner, but if this is a concern for you and want
to use the system library instead; abort this installation process and
reinstall nokogiri as follows:

    gem install nokogiri -- --use-system-libraries
        [--with-xml2-config=/path/to/xml2-config]
        [--with-xslt-config=/path/to/xslt-config]

If you are using Bundler, tell it to use the option:

    bundle config build.nokogiri --use-system-libraries
    bundle install

Note, however, that nokogiri is not fully compatible with arbitrary
versions of libxml2 provided by OS/package vendors.
************************************************************************
Extracting libxml2-2.9.4.tar.gz into tmp/x86_64-apple-darwin15/ports/libxml2/2.9.4... OK
Running 'configure' for libxml2 2.9.4... OK
Running 'compile' for libxml2 2.9.4... ERROR, review 'tmp/ruby/2.0.0/gems/nokogiri-1.6.8/ext/nokogiri/tmp/x86_64-apple-darwin15/ports/libxml2/2.9.4/compile.log' to see what happened. Last lines are:
========================================================================
  CCLD     libxml2.la
  CC       testdso.lo
  CCLD     testdso.la
  CC       xmllint.o
  CCLD     xmllint
ld: warning: ignoring file /usr/local/Cellar/xz/5.2.2/lib/liblzma.dylib, file was built for x86_64 which is not the architecture being linked (i386): /usr/local/Cellar/xz/5.2.2/lib/liblzma.dylib
Undefined symbols for architecture i386:
  "_lzma_auto_decoder", referenced from:
      _xz_head in libxml2.a(xzlib.o)
  "_lzma_code", referenced from:
      _xz_decomp in libxml2.a(xzlib.o)
  "_lzma_end", referenced from:
      ___libxml2_xzclose in libxml2.a(xzlib.o)
  "_lzma_properties_decode", referenced from:
      _is_format_lzma in libxml2.a(xzlib.o)
ld: symbol(s) not found for architecture i386
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make[2]: *** [xmllint] Error 1
make[1]: *** [all-recursive] Error 1
make: *** [all] Error 2
========================================================================
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of necessary
libraries and/or headers.  Check the mkmf.log file for more details.  You may
need configuration options.

Provided configuration options:
    --with-opt-dir
    --without-opt-dir
    --with-opt-include
    --without-opt-include=${opt-dir}/include
    --with-opt-lib
    --without-opt-lib=${opt-dir}/lib
    --with-make-prog
    --without-make-prog
    --srcdir=.
    --curdir
    --ruby=/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/bin/ruby
    --help
    --clean
    --use-system-libraries
    --enable-static
    --disable-static
    --with-zlib-dir
    --without-zlib-dir
    --with-zlib-include
    --without-zlib-include=${zlib-dir}/include
    --with-zlib-lib
    --without-zlib-lib=${zlib-dir}/lib
    --enable-cross-build
    --disable-cross-build
tmp/ruby/2.0.0/gems/mini_portile2-2.1.0/lib/mini_portile2/mini_portile.rb:366:in `block in execute': Failed to complete compile task (RuntimeError)
    from tmp/ruby/2.0.0/gems/mini_portile2-2.1.0/lib/mini_portile2/mini_portile.rb:337:in `chdir'
    from tmp/ruby/2.0.0/gems/mini_portile2-2.1.0/lib/mini_portile2/mini_portile.rb:337:in `execute'
    from tmp/ruby/2.0.0/gems/mini_portile2-2.1.0/lib/mini_portile2/mini_portile.rb:111:in `compile'
    from tmp/ruby/2.0.0/gems/mini_portile2-2.1.0/lib/mini_portile2/mini_portile.rb:150:in `cook'
    from extconf.rb:364:in `block (2 levels) in process_recipe'
    from extconf.rb:257:in `block in chdir_for_build'
    from extconf.rb:256:in `chdir'
    from extconf.rb:256:in `chdir_for_build'
    from extconf.rb:363:in `block in process_recipe'
    from extconf.rb:262:in `tap'
    from extconf.rb:262:in `process_recipe'
    from extconf.rb:555:in `<main>'

To see why this extension failed to compile, please check the mkmf.log which can be found here:

  tmp/ruby/2.0.0/extensions/universal-darwin-15/2.0.0/nokogiri-1.6.8/mkmf.log

extconf failed, exit code 1

Gem files will remain installed in tmp/ruby/2.0.0/gems/nokogiri-1.6.8 for inspection.
Results logged to tmp/ruby/2.0.0/extensions/universal-darwin-15/2.0.0/nokogiri-1.6.8/gem_make.out

Contents of mkmf.log:

→ cat ruby/2.0.0/extensions/universal-darwin-15/2.0.0/nokogiri-1.6.8/mkmf.log
"xcrun clang -o conftest -I/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/include/ruby-2.0.0/universal-darwin15 -I/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/include/ruby-2.0.0/ruby/backward -I/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/include/ruby-2.0.0 -I. -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE -D_DARWIN_UNLIMITED_SELECT -D_REENTRANT    -g -Os -pipe -DHAVE_GCC_SYNC_BUILTINS  conftest.c  -L. -L/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib -L. -L/usr/local/lib   -arch x86_64 -arch i386   -lruby.2.0.0  -lpthread -ldl -lobjc  "
checked program was:
/* begin */
1: #include "ruby.h"
2:
3: int main(int argc, char **argv)
4: {
5:   return 0;
6: }
/* end */

"xcrun clang -I/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/include/ruby-2.0.0/universal-darwin15 -I/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/include/ruby-2.0.0/ruby/backward -I/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/include/ruby-2.0.0 -I. -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE -D_DARWIN_UNLIMITED_SELECT -D_REENTRANT    -g -Os -pipe -DHAVE_GCC_SYNC_BUILTINS   -arch x86_64 -arch i386  -c conftest.c"
checked program was:
/* begin */
1: #include "ruby.h"
2:
3: int main() {return 0;}
/* end */

"xcrun clang -I/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/include/ruby-2.0.0/universal-darwin15 -I/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/include/ruby-2.0.0/ruby/backward -I/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/include/ruby-2.0.0 -I. -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE -D_DARWIN_UNLIMITED_SELECT -D_REENTRANT    -g -Os -pipe -DHAVE_GCC_SYNC_BUILTINS  -Wno-error=unused-command-line-argument-hard-error-in-future  -arch x86_64 -arch i386  -c conftest.c"
warning: unknown warning option '-Werror=unused-command-line-argument-hard-error-in-future'; did you mean '-Werror=unused-command-line-argument'? [-Wunknown-warning-option]
1 warning generated.
warning: unknown warning option '-Werror=unused-command-line-argument-hard-error-in-future'; did you mean '-Werror=unused-command-line-argument'? [-Wunknown-warning-option]
1 warning generated.
checked program was:
/* begin */
1: #include "ruby.h"
2:
3: int main() {return 0;}
/* end */

have_header: checking for iconv.h... -------------------- yes

"xcrun clang -I/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/include/ruby-2.0.0/universal-darwin15 -I/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/include/ruby-2.0.0/ruby/backward -I/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/include/ruby-2.0.0 -I. -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE -D_DARWIN_UNLIMITED_SELECT -D_REENTRANT    -g -Os -pipe -DHAVE_GCC_SYNC_BUILTINS   -arch x86_64 -arch i386  -c conftest.c"
checked program was:
/* begin */
1: #include "ruby.h"
2:
3: #include <iconv.h>
/* end */

--------------------

have_library: checking for gzdopen() in -lz... -------------------- yes

"xcrun clang -o conftest -I/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/include/ruby-2.0.0/universal-darwin15 -I/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/include/ruby-2.0.0/ruby/backward -I/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/include/ruby-2.0.0 -I. -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE -D_DARWIN_UNLIMITED_SELECT -D_REENTRANT    -g -Os -pipe -DHAVE_GCC_SYNC_BUILTINS  conftest.c  -L. -L/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib -L. -L/usr/local/lib   -arch x86_64 -arch i386   -lruby.2.0.0 -lz  -lpthread -ldl -lobjc  "
checked program was:
/* begin */
 1: #include "ruby.h"
 2:
 3: #include <zlib.h>
 4:
 5: /*top*/
 6: extern int t(void);
 7: int t(void) { void ((*volatile p)()); p = (void ((*)()))gzdopen; return 0; }
 8: int main(int argc, char **argv)
 9: {
10:   if (argc > 1000000) {
11:     printf("%p", &t);
12:   }
13:
14:   return 0;
15: }
/* end */

--------------------

have_iconv?: checking for iconv... -------------------- yes

"xcrun clang -o conftest -I/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/include/ruby-2.0.0/universal-darwin15 -I/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/include/ruby-2.0.0/ruby/backward -I/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/include/ruby-2.0.0 -I. -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE -D_DARWIN_UNLIMITED_SELECT -D_REENTRANT    -g -Os -pipe -DHAVE_GCC_SYNC_BUILTINS  conftest.c  -L. -L/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib -L. -L/usr/local/lib   -arch x86_64 -arch i386   -lruby.2.0.0  -lpthread -ldl -lobjc  "
Undefined symbols for architecture x86_64:
  "_iconv", referenced from:
      _main in conftest-ba1623.o
  "_iconv_open", referenced from:
      _main in conftest-ba1623.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
checked program was:
/* begin */
 1: #include "ruby.h"
 2:
 3: #include <stdlib.h>
 4: #include <iconv.h>
 5:
 6: int main(void)
 7: {
 8:     iconv_t cd = iconv_open("", "");
 9:     iconv(cd, NULL, NULL, NULL, NULL);
10:     return EXIT_SUCCESS;
11: }
/* end */

"xcrun clang -o conftest -I/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/include/ruby-2.0.0/universal-darwin15 -I/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/include/ruby-2.0.0/ruby/backward -I/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/include/ruby-2.0.0 -I. -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE -D_DARWIN_UNLIMITED_SELECT -D_REENTRANT    -g -Os -pipe -DHAVE_GCC_SYNC_BUILTINS  conftest.c  -L. -L/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib -L. -L/usr/local/lib   -arch x86_64 -arch i386   -lruby.2.0.0 -liconv -lpthread -ldl -lobjc  "
checked program was:
/* begin */
 1: #include "ruby.h"
 2:
 3: #include <stdlib.h>
 4: #include <iconv.h>
 5:
 6: int main(void)
 7: {
 8:     iconv_t cd = iconv_open("", "");
 9:     iconv(cd, NULL, NULL, NULL, NULL);
10:     return EXIT_SUCCESS;
11: }
/* end */

--------------------

[BenMorganIO]

This worked for me:

gem install nokogiri -- --with-xml2-include=/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.11.sdk/usr/include/libxml2 --use-system-libraries

[au5ton]

This worked for me when attempting to install github/pages-gem. Thanks @md5.

[CyborgMaster]

xcode-select --install worked for me

[phantompatrol]

Related or dupe to #1486? Given that (subjectively) the symptoms and solution were similar for me.

[timurcatakli]

I had the same nokogiri install problem. My repo folder was in a box.com sync folder. I moved it to another folder and it installed without any problems. So make sure that you are not using a box.com folder.

Thanks