Does not compile

It fails compiling under Ubuntu 20 with

[ 94%] Built target lua
[ 97%] Linking CXX executable raylib-lua-sol
/usr/bin/ld: ../liblua.a(loslib.c.o): in function `os_tmpname':
loslib.c:(.text+0x18b): warning: the use of `tmpnam' is dangerous, better use `mkstemp'
/usr/bin/ld: CMakeFiles/raylib-lua-sol.dir/raylib-lua-sol.cpp.o: in function `raylib_lua_sol_rlgl(sol::state&)':
raylib-lua-sol.cpp:(.text+0xce9): undefined reference to `rlUnproject'
/usr/bin/ld: CMakeFiles/raylib-lua-sol.dir/raylib-lua-sol.cpp.o: in function `raylib_lua_sol_functions(sol::state&)':
raylib-lua-sol.cpp:(.text+0xa867): undefined reference to `LoadImageEx'
/usr/bin/ld: raylib-lua-sol.cpp:(.text+0xadb0): undefined reference to `ImageExtractPalette'
/usr/bin/ld: raylib-lua-sol.cpp:(.text+0xc799): undefined reference to `SetMusicLoopCount'
collect2: error: ld returned 1 exit status
make[2]: *** [bin/CMakeFiles/raylib-lua-sol.dir/build.make:86: bin/raylib-lua-sol] Error 1
make[1]: *** [CMakeFiles/Makefile2:970: bin/CMakeFiles/raylib-lua-sol.dir/all] Error 2

I then took out ImageExtraPalette and SetMusicLoopCount from include/raylib-lua-sol.hpp but the rlUnproject and LoadImageEx undefied references stay.

Start by inspecting include/raylib-lua-sol.hpp and the linked raylib-lua-sol.cpp object, then review the CMake link configuration that produces the raylib-lua-sol executable. Reproduce the Ubuntu 20 build and trace the unresolved rlUnproject and LoadImageEx references; done means the executable links without these errors.