Work around another seeminly random mis-optimization by Apple's Clang with -Oz

If it wasn't for the desperate need to minimize code size for LO-based
iOS apps, I definitely wouldn't use -Oz in gb_COMPILERDEFAULTOPTFLAGS
(in solenv/gbuild/platform/IOS_ARM_GCC.mk).

Change-Id: Icb231b5f30b32afe1c0f3b43e5744bf0e41e96df

oox/Library_oox.mk

@@ -129,7 +129,6 @@ $(eval $(call gb_Library_add_exception_objects,oox,\
     oox/source/drawingml/clrschemecontext \
     oox/source/drawingml/clrscheme \
     oox/source/drawingml/colorchoicecontext \
-    oox/source/drawingml/color \
     oox/source/drawingml/connectorshapecontext \
     oox/source/drawingml/customshapegeometry \
     oox/source/drawingml/customshapepresetdata \
@@ -292,4 +291,19 @@ $(eval $(call gb_Library_add_exception_objects,oox,\
     oox/source/vml/vmltextbox \
 ))
 
+ifeq ($(OS),IOS)
+# Either a compiler bug in Xcode 5.1.1 or some hard-to-spot undefined
+# behaviour in the source code... Compiling this source file with
+# optimization causes some Smart Art images to end up with completely
+# wrong colour, some even totally black.
+$(eval $(call gb_Library_add_cxxobjects,oox,\
+    oox/source/drawingml/color \
+    , $(gb_COMPILERNOOPTFLAGS) $(gb_LinkTarget_EXCEPTIONFLAGS) \
+))
+else
+$(eval $(call gb_Library_add_exception_objects,oox,\
+    oox/source/drawingml/color \
+))
+endif
+
 # vim: set noet sw=4 ts=4: