Macos constexpr constructor failure w/o -std=c++2b flag for clang

[god-shatter]

Compilation on my mac won't work unless I append the explicit std version flag -std=c++2b to the makefile CXXFlags.
It trips up on a constexpr constructor.

-> clang --version
Apple clang version 14.0.3 (clang-1403.0.22.14.1)
Target: arm64-apple-darwin23.1.0
Thread model: posix
InstalledDir: /Library/Developer/CommandLineTools/usr/bin

After fixing that and trying to run the glfw/opengl3 backend it errors on an incorrect linking call to ld.

➜  example_glfw_opengl3 git:(docking_inter) ✗ make
[ 59%] Built target glfw
[ 62%] Building CXX object CMakeFiles/cimgui.dir/Users/sugar/code/cimgui/cimgui.cpp.o
[ 66%] Linking CXX shared library libcimgui.dylib
ld: library not found for -lGL
clang: error: linker command failed with exit code 1 (use -v to see invocation)

For macos (m1 atleast) it should be -framework OpenGL to link opengl

EDIT2:

OK I got the example to build by changing the CMake OpenGL linking logic for macos to:

find_library(OPENGL OpenGL)
if (NOT OPENGL)
    message(FATAL_ERROR "OPENGL not found")
endif()
target_link_libraries(${PROJECT_NAME} ${OPENGL})

apparently find_library has special handling for macos

EDIT3:

Ah ok, so the backend_test example build processes will output a dll with the backend symbols exported. I get it now.

[sonoro1234]

I cant test on macosx so PR is welcome