set c++ standard exactly to 14. The standard is set globally for the project.

Author: moritzx22

CMakeLists.txt

@@ -8,6 +8,10 @@ option(NINJA_FORCE_PSELECT "Use pselect() even on platforms that provide ppoll()
 
 project(ninja CXX)
 
+set(CMAKE_CXX_STANDARD 14)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+set(CMAKE_CXX_EXTENSIONS OFF)
+
 # --- optional link-time optimization
 check_ipo_supported(RESULT lto_supported OUTPUT error)
 
@@ -191,9 +195,6 @@ else()
 	endif()
 endif()
 
-target_compile_features(libninja PUBLIC cxx_std_14)
-target_compile_features(libninja-re2c PUBLIC cxx_std_14)
-
 #Fixes GetActiveProcessorCount on MinGW
 if(MINGW)
 target_compile_definitions(libninja PRIVATE _WIN32_WINNT=0x0601 __USE_MINGW_ANSI_STDIO=1)