make linker error compiling on arm64 macos

[emilyinure]

make output

[ 88%] Linking CXX shared library libopenage.dylib
ld: warning: -undefined error is deprecated
Undefined symbols for architecture arm64:
  "openage::util::consteval_::strip_prefix(char const*, char const*)", referenced from:
      openage::renderer::opengl::GlShaderProgram::GlShaderProgram(std::__1::shared_ptr<openage::renderer::opengl::GlContext> const&, std::__1::vector<openage::renderer::resources::ShaderSource, std::__1::allocator<openage::renderer::resources::ShaderSource>> const&) in shader_program.cpp.o
      openage::datastructure::ConstMap<unsigned int, unsigned long, 28ul>::get(unsigned int const&) const in uniform_buffer.cpp.o
ld: symbol(s) not found for architecture arm64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make[3]: *** [libopenage/libopenage.0.dylib] Error 1
make[2]: *** [libopenage/CMakeFiles/libopenage.dir/all] Error 2
make[1]: *** [all] Error 2
make: *** [build] Error 2

[heinezen]

I've looked into this and the issue seems to be that AppleClang is too outdated to compile this code properly. I have updated the instructions in #1698 to make this more clear.

[TheJJ]

I've merged the pull, please report back when you still encounter linker errors with clang.