build ODK headers check without LIBO_INTERNAL_ONLY

Change-Id: Ia8bca09a877bed6070c10e1c008bdb05ac088485

odk/CppunitTest_odk_checkapi.mk

@@ -23,6 +23,12 @@ $(eval $(call gb_CppunitTest_use_internal_comprehensive_api,odk_checkapi,\
 	udkapi \
 ))
 
+$(eval $(call gb_CppunitTest_disable_compiler_plugins,odk_checkapi))
+
+$(eval $(call gb_CppunitTest_add_cxxflags,odk_checkapi,\
+	$(gb_CXXFLAGS_Wundef) \
+))
+
 $(eval $(call gb_CppunitTest_use_libraries,odk_checkapi,\
 	cppu \
 	cppuhelper \

odk/qa/checkapi/checkapi.cxx

@@ -7,6 +7,9 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
+// Acts as if building outside of LO.
+#undef LIBO_INTERNAL_ONLY
+
 // The whole purpose of this test is to check that public API headers
 // build even without RTL_USING (which enables using e.g. rtl::OUString
 // without to refer to the rtl namespace, which is not wanted

solenv/gbuild/platform/com_GCC_defs.mk

@@ -70,6 +70,8 @@ gb_CXXFLAGS_COMMON := \
 	-fno-common \
 	-pipe \
 
+gb_CXXFLAGS_Wundef = -Wno-undef
+
 ifneq ($(HAVE_THREADSAFE_STATICS),TRUE)
 gb_CXXFLAGS_COMMON += -fno-threadsafe-statics
 endif