Filter out non-interesting -Wvariadic-macros / -Werror=non-virtual-dtor

- 'anonymous variadic macros were introduced in C99' is not interesting
  when building with -std=gnu++03
- 'class cppu::PropertySetMixinImpl has virtual functions and accessible
  non-virtual destructor' is not interesting when we implicitly disable
  the ability to disable warnings from code

Change-Id: I391817f9fc793d9b38f97111138aebd63c3a443f

solenv/gbuild/platform/com_GCC_defs.mk

@@ -102,7 +102,7 @@ ifeq ($(COM_GCC_IS_CLANG),TRUE)
 # doesn't know gnu++03 and this seems to be the same anyway
 gb_CXX03FLAGS := -std=gnu++98 -Werror=c++11-extensions -Wno-c++11-long-long
 else
-gb_CXX03FLAGS := -std=gnu++03 -pedantic-errors -Wno-long-long
+gb_CXX03FLAGS := -std=gnu++03 -pedantic-errors -Wno-long-long -Wno-variadic-macros -Wno-non-virtual-dtor
 endif
 
 ifeq ($(ENABLE_LTO),TRUE)