customizable c++ version

87c41673da119e1384d9b3fffedae5d40c385e0c

build/conf/compilers/gnu_compiler.conf

@@ -1,3 +1,5 @@
+_STD_CXX=-std=$_STD_CXX_VERSION
+
 _OPTIMIZE_RELEASE=
 when ($_BUILD_RELEASE == "yes") {
     when ($_BUILD_SIZE_OPTIMIZED == "yes") {
@@ -72,7 +74,7 @@ when ($OS_EMSCRIPTEN == "yes") {
 }
 
 CFLAGS+=$_C_FLAGS $DEBUG_INFO_FLAGS $_C_FOPTIONS $C_WARNING_OPTS $GCC_PREPROCESSOR_OPTS $USER_CFLAGS $USER_CFLAGS_GLOBAL
-CXXFLAGS+=$CFLAGS $_CXX_STD $CXX_WARNING_OPTS $USER_CXXFLAGS $USER_CXXFLAGS_GLOBAL
+CXXFLAGS+=$CFLAGS $_STD_CXX $CXX_WARNING_OPTS $USER_CXXFLAGS $USER_CXXFLAGS_GLOBAL
 CONLYFLAGS+=$USER_CONLYFLAGS $USER_CONLYFLAGS_GLOBAL
 CXX_COMPILER=${quo:CXX_COMPILER_UNQUOTED}
 NOGCCSTACKCHECK=yes

build/conf/compilers/msvc_compiler.conf

@@ -1,3 +1,5 @@
+_STD_CXX=/std:$_STD_CXX_VERSION
+
 MSVC_INLINE_OPTIMIZED=yes
 when ($MSVC_INLINE_OPTIMIZED == "yes") {
     MSVC_INLINE_FLAG=/Zc:inline

build/conf/settings.conf

@@ -41,7 +41,6 @@ _FOLDABLE_VARS=\
     _CROSS_SUFFIX \
     _CXX_DEFINES \
     _CXX_FLAGS \
-    _CXX_STD \
     _C_ARGS \
     _C_CPP_KV_STYLE \
     _C_FLAGS \
@@ -105,5 +104,6 @@ _FOLDABLE_VARS=\
     _SONAME_OPTION \
     _START_GROUP \
     _STD_CXX \
+    _STD_CXX_VERSION \
 
 # end of _FOLDABLE_VARS list

build/ymake_conf.py

@@ -504,7 +504,7 @@ class Options(object):
         self.toolchain_params = self.options.toolchain_params
 
         self.presets = parse_presets(self.options.presets)
-        userify_presets(self.presets, ('CFLAGS', 'CXXFLAGS', 'CONLYFLAGS', 'LDFLAGS', 'GO_COMPILE_FLAGS', 'GO_LINK_FLAGS'))
+        userify_presets(self.presets, ('CFLAGS', 'CXXFLAGS', 'CONLYFLAGS', 'LDFLAGS', 'GO_COMPILE_FLAGS', 'GO_LINK_FLAGS', 'STD_CXX_VERSION'))
 
     Instance = None
 
@@ -1588,7 +1588,7 @@ class GnuCompiler(Compiler):
         emit('WERROR_MODE', self.tc.werror_mode)
         emit('_C_FLAGS', self.c_flags)
         emit('_C_FOPTIONS', self.c_foptions)
-        emit('_CXX_STD', '-std={}'.format(self.tc.cxx_std))
+        emit('_STD_CXX_VERSION', preset('USER_STD_CXX_VERSION') or self.tc.cxx_std)
         append('C_DEFINES', self.c_defines)
         append('C_WARNING_OPTS', self.c_warnings)
         append('CXX_WARNING_OPTS', self.cxx_warnings)
@@ -2111,7 +2111,7 @@ class MSVCCompiler(MSVC, Compiler):
         if self.build.is_ide:
             emit('CFLAGS_PER_TYPE', '@[debug|$CFLAGS_DEBUG]@[release|$CFLAGS_RELEASE]')
 
-        emit('_STD_CXX', '/std:{}'.format(self.tc.cxx_std))
+        emit('_STD_CXX_VERSION', preset('USER_STD_CXX_VERSION') or self.tc.cxx_std)
 
         emit('_MSVC_FLAGS', flags)