Fix unrecognized -Wv:18 option for clang-cl on MSVC 14.0

Change-Id: I4ac94475b663c1ec1f5148b766a81a31adb1d49e
Reviewed-on: https://gerrit.libreoffice.org/23038Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

solenv/gbuild/platform/com_MSC_defs.mk

@@ -164,7 +164,6 @@ gb_CFLAGS := \
 	-wd4706 \
 	-wd4800 \
 	-Zc:wchar_t- \
-	$(if $(filter-out 120,$(VCVER)), -Wv:18 -wd4267) \
 
 ifeq ($(COM_IS_CLANG),TRUE)
 gb_CFLAGS += \
@@ -175,6 +174,11 @@ gb_CFLAGS += \
 	-Wundef \
 	-Wunused-macros \
 
+else
+
+gb_CFLAGS += \
+	$(if $(filter-out 120,$(VCVER)), -Wv:18 -wd4267) \
+
 endif
 
 gb_CXXFLAGS := \
@@ -207,7 +211,6 @@ gb_CXXFLAGS := \
 	-wd4800 \
 	-wd4913 \
 	-Zc:wchar_t- \
-	$(if $(filter-out 120,$(VCVER)), -Wv:18 -wd4267) \
 
 ifeq ($(CPUNAME),X86_64)
 
@@ -235,6 +238,11 @@ gb_CXXFLAGS += \
 	-Wundef \
 	-Wunused-macros \
 
+else
+
+gb_CXXFLAGS += \
+	$(if $(filter-out 120,$(VCVER)), -Wv:18 -wd4267) \
+
 endif
 
 # rc.exe does not support -nologo in 6.1.6723.1 that is in the Windows SDK 6.0A