libwpg: pass optimization flags to configure

Change-Id: Id49c3d10aa3dc6c6cabcb23a382f2c3d3a58d1a8
Reviewed-on: https://gerrit.libreoffice.org/44005Reviewed-by: David Tardon <dtardon@redhat.com>
Tested-by: David Tardon <dtardon@redhat.com>

external/libwpg/ExternalProject_libwpg.mk

@@ -35,6 +35,7 @@ $(call gb_ExternalProject_get_state_target,libwpg,build) :
 			$(if $(filter MACOSX,$(OS)),--prefix=/@.__________________________________________________OOO) \
 			$(if $(verbose),--disable-silent-rules,--enable-silent-rules) \
 			$(if $(CROSS_COMPILING),--build=$(BUILD_PLATFORM) --host=$(HOST_PLATFORM)) \
+			CXXFLAGS="$(gb_CXXFLAGS) $(if $(ENABLE_OPTIMIZED),$(gb_COMPILEROPTFLAGS),$(gb_COMPILERNOOPTFLAGS))" \
 			$(if $(filter LINUX,$(OS)), \
 				'LDFLAGS=-Wl$(COMMA)-z$(COMMA)origin \
 					-Wl$(COMMA)-rpath$(COMMA)\$$$$ORIGIN') \