Missing test source causes broken configuration on macOS

[PikalaxALT]

Installing s2 via BioConductor attempts to use /usr/local/opt/openssl as the search path for libssl and libcrypto but tries to load libssl.1.0.0.dylib which is not a valid library in that folder, therefore I tried github master which modifies configure#L36 to specify openssl@1.1, however this did not resolve the issue.

System: Intel MacBook Pro running Big Sur

Homebrew: installed openssl@1.0, openssl@1.1, openssl@3.0

R version 4.1.1 Kick Things

To reproduce:

devtools::install_github("https://github.com/r-spacial/s2")

Observation:

─  installing *source* package ‘s2’ ...
   ** using staged installation
   Homebrew 3.2.15-41-g5af25ee
   Homebrew/homebrew-core (git revision 922cafb4889; last commit 2021-10-08)
   Homebrew/homebrew-cask (git revision d5e8cc7caa; last commit 2021-10-08)
   Testing compiler using PKG_CFLAGS=-I/usr/local/opt/openssl@1.1/include
   Using PKG_LIBS=-L/usr/local/opt/openssl@1.1/lib -lssl -lcrypto
   Using PKG_CFLAGS=-I/usr/local/opt/openssl@1.1/include -DIS_LITTLE_ENDIAN

...

   ** testing if installed package can be loaded from temporary location
   Error: package or namespace load failed for ‘s2’ in dyn.load(file, DLLpath = DLLpath, ...):
    unable to load shared object '/private/var/folders/xg/1clp6x614c722qd1qvmwc72h0000gn/T/RtmpTmlls3/Rinst111bd41a6ed7b/00LOCK-s2/00new/s2/libs/s2.so':
     dlopen(/private/var/folders/xg/1clp6x614c722qd1qvmwc72h0000gn/T/RtmpTmlls3/Rinst111bd41a6ed7b/00LOCK-s2/00new/s2/libs/s2.so, 6): Library not loaded: /usr/local/opt/openssl/lib/libssl.1.0.0.dylib
     Referenced from: /private/var/folders/xg/1clp6x614c722qd1qvmwc72h0000gn/T/RtmpTmlls3/Rinst111bd41a6ed7b/00LOCK-s2/00new/s2/libs/s2.so
     Reason: image not found
   Error: loading failed
   Execution halted
   ERROR: loading failed

[PikalaxALT]

It appears that src/tests/main.c is missing in the git clone, which impacts configuration.

[PikalaxALT]

I created a dummy src/tests/main.c file which includes <openssl/ssl.h>, calls a library method from that header, and prints "Hello, world!". The resulting configuration generates a successful build.