gbuild: enable -Wnon-virtual-dtor for all GCC platforms

It was disabled globally at a time when GCC did not yet support #pragma
GCC diagnostic.

Change-Id: I062f6b437e6119203f2b0824a25238b45b4f4e79

solenv/gbuild/platform/IOS_ARM_GCC.mk

@@ -47,13 +47,9 @@ gb_CFLAGS := \
 	-Wshadow \
 	-fno-strict-aliasing \
 
-# For -Wno-non-virtual-dtor see <http://markmail.org/message/664jsoqe6n6smy3b>
-# "Re: [dev] warnings01: -Wnon-virtual-dtor" message to dev@openoffice.org from
-# Feb 1, 2006:
 gb_CXXFLAGS := \
 	$(gb_CXXFLAGS_COMMON) \
 	-Wno-ctor-dtor-privacy \
-	-Wno-non-virtual-dtor \
 	-fno-strict-aliasing \
 	-fsigned-char \
 	$(CXXFLAGS_CXX11) \

solenv/gbuild/platform/com_GCC_defs.mk

@@ -62,6 +62,7 @@ gb_CFLAGS_COMMON := \
 
 gb_CXXFLAGS_COMMON := \
 	-Wall \
+	-Wnon-virtual-dtor \
 	-Wendif-labels \
 	-Wextra \
 	-Wundef \

solenv/gbuild/platform/macosx.mk

@@ -46,14 +46,10 @@ gb_CFLAGS := \
 	-fno-strict-aliasing \
     #-Wshadow \ break in compiler headers already
 
-# For -Wno-non-virtual-dtor see <http://markmail.org/message/664jsoqe6n6smy3b>
-# "Re: [dev] warnings01: -Wnon-virtual-dtor" message to dev@openoffice.org from
-# Feb 1, 2006:
 gb_CXXFLAGS := \
 	$(gb_CXXFLAGS_COMMON) \
 	-fPIC \
 	-Wno-ctor-dtor-privacy \
-	-Wno-non-virtual-dtor \
 	-fno-strict-aliasing \
 	-fsigned-char \
 	$(CXXFLAGS_CXX11)

solenv/gbuild/platform/mingw.mk

@@ -36,13 +36,9 @@ gb_CFLAGS += \
 	-Wdeclaration-after-statement \
 	-fno-strict-aliasing \
 
-# For -Wno-non-virtual-dtor see <http://markmail.org/message/664jsoqe6n6smy3b>
-# "Re: [dev] warnings01: -Wnon-virtual-dtor" message to dev@openoffice.org from
-# Feb 1, 2006:
 gb_CXXFLAGS := \
 	$(gb_CXXFLAGS_COMMON) \
 	-Wno-ctor-dtor-privacy \
-	-Wno-non-virtual-dtor \
 	-Wreturn-type \
 	-Wshadow \
 	-Wuninitialized \

solenv/gbuild/platform/solaris.mk

@@ -61,7 +61,6 @@ gb_CXXFLAGS := \
 	-fPIC \
 	-Wshadow \
 	-Woverloaded-virtual \
-	-Wnon-virtual-dtor \
 	-std=c++0x \
 
 # enable debug STL

solenv/gbuild/platform/unxgcc.mk

@@ -43,7 +43,6 @@ gb_CXXFLAGS := \
 	-fPIC \
 	-Wshadow \
 	-Woverloaded-virtual \
-	-Wnon-virtual-dtor \
 	$(CXXFLAGS_CXX11) \