cmake HAS_EXP_17_FS_WITH_CLIB examples

Wargus/wargus CMakeLists.txt :219 

check_cxx_source_compiles("${EXPERIMENTAL_FS_SRC}" HAS_EXP_17_FS_WITH_CLIB)

Wargus/stratagus CMakeLists.txt :637 

check_cxx_source_compiles("${EXPERIMENTAL_FS_SRC}" HAS_EXP_17_FS_WITH_CLIB)