Compiler assumption on MacOS

[cmichelenstrofer]

When I try pip install pygalmesh I get the following error:

gcc: error: unrecognized command-line option '-stdlib=libc++' error: command '/opt/local/bin/gcc' failed with exit code 1

Based on this answer I suspect the assumption is that Clang is used instead GNU compilers. It sounds like that option can be deleted or replaced with -stdlib=libstdc++ since both compilers can use it.