Require C++17 as minimal

Signed-off-by: Uilian Ries <uilianries@gmail.com>

Author: uilianries

CMakeLists.txt

@@ -47,7 +47,7 @@ message(STATUS "Architecture as detected by CMake: ${CMAKE_SYSTEM_PROCESSOR}")
 # Build configuration
 add_compile_definitions(GNUSTEP __OBJC_RUNTIME_INTERNAL__=1 __OBJC_BOOL)
 
-set(CMAKE_CXX_STANDARD 17)
+
 
 set(libobjc_ASM_SRCS 
 	block_trampolines.S
@@ -259,6 +259,7 @@ endif ()
 
 add_library(objc SHARED ${libobjc_C_SRCS} ${libobjc_ASM_SRCS} ${libobjc_OBJC_SRCS} ${libobjc_OBJCXX_SRCS} ${libobjc_ASM_OBJS})
 target_compile_options(objc PRIVATE "$<$<OR:$<COMPILE_LANGUAGE:OBJC>,$<COMPILE_LANGUAGE:OBJCXX>>:-Wno-gnu-folding-constant;-Wno-deprecated-objc-isa-usage;-Wno-objc-root-class;-fobjc-runtime=gnustep-2.0>$<$<COMPILE_LANGUAGE:C>:-Xclang;-fexceptions;-Wno-gnu-folding-constant>")
+target_compile_features(objc PRIVATE cxx_std_17)
 
 list(APPEND libobjc_CXX_SRCS ${libobjcxx_CXX_SRCS})
 target_sources(objc PRIVATE ${libobjc_CXX_SRCS})