Use gb_OBJCXXFLAGS for iOS, too

vcl/Library_vcl.mk

@@ -236,9 +236,8 @@ $(eval $(call gb_Library_add_nativeres,vcl,src))
 endif
 
 ifeq ($(GUIBASE),cocoatouch)
-$(eval $(call gb_Library_set_cxxflags,vcl,\
-    $$(CXXFLAGS) \
-    $$(OBJCXXFLAGS) \
+$(eval $(call gb_Library_add_cxxflags,vcl,\
+    $(gb_OBJCXXFLAGS) \
 ))
 $(eval $(call gb_Library_add_objcxxobjects,vcl,\
     vcl/ios/source/app/salnstimer \

vcl/StaticLibrary_vclmain.mk

@@ -28,9 +28,8 @@
 $(eval $(call gb_StaticLibrary_StaticLibrary,vclmain))
 
 ifeq ($(OS),IOS)
-$(eval $(call gb_StaticLibrary_set_cxxflags,vclmain,\
-    $$(CXXFLAGS) \
-    -x objective-c++ -fobjc-abi-version=2 -fobjc-legacy-dispatch -D__IPHONE_OS_VERSION_MIN_REQUIRED=40300 \
+$(eval $(call gb_StaticLibrary_add_cxxflags,vclmain,\
+    $(gb_OBJCXXFLAGS) \
 ))
 endif