fix bug with handling target’s language standard properties

CMake/cotire.cmake

@@ -454,14 +454,16 @@ function (cotire_get_target_compile_flags _config _language _target _flagsVar)
 		# used compiler supports language standard levels
 		if (_target)
 			get_target_property(_targetLanguageStandard ${_target} ${_language}_STANDARD)
-			get_target_property(_targetLanguageExtensions ${_target} ${_language}_EXTENSIONS)
-			if (_targetLanguageExtensions)
-				if (CMAKE_${_language}${_targetLanguageExtensions}_EXTENSION_COMPILE_OPTION)
-					list (APPEND _compileFlags "${CMAKE_${_language}${_targetLanguageExtensions}_EXTENSION_COMPILE_OPTION}")
-				endif()
-			elseif (_targetLanguageStandard)
-				if (CMAKE_${_language}${_targetLanguageStandard}_EXTENSION_COMPILE_OPTION)
-					list (APPEND _compileFlags "${CMAKE_${_language}${_targetLanguageStandard}_EXTENSION_COMPILE_OPTION}")
+			if (_targetLanguageStandard)
+				get_target_property(_targetLanguageExtensions ${_target} ${_language}_EXTENSIONS)
+				if (_targetLanguageExtensions)
+					if (CMAKE_${_language}${_targetLanguageStandard}_EXTENSION_COMPILE_OPTION)
+						list (APPEND _compileFlags "${CMAKE_${_language}${_targetLanguageStandard}_EXTENSION_COMPILE_OPTION}")
+					endif()
+				else()
+					if (CMAKE_${_language}${_targetLanguageStandard}_STANDARD_COMPILE_OPTION)
+						list (APPEND _compileFlags "${CMAKE_${_language}${_targetLanguageStandard}_STANDARD_COMPILE_OPTION}")
+					endif()
 				endif()
 			endif()
 		endif()