Fix XPCOM tests linkage error on Darwin (only visible on clobber builds that build tests). r/sr=bryner.

xpcom/sample/Makefile.in

@@ -80,6 +80,17 @@ ifeq ($(OS_ARCH)$(OS_RELEASE),FreeBSD2)
 LIBS		+= -lpcap
 endif
 
+# Need to link with CoreFoundation on Mac
+ifneq (,$(filter mac cocoa,$(MOZ_WIDGET_TOOLKIT)))
+EXTRA_DSO_LDOPTS += \
+		$(TK_LIBS) \
+		$(NULL)
+
+LIBS += \
+		$(TK_LIBS) \
+		$(NULL)
+endif
+
 include $(topsrcdir)/config/rules.mk
 
 libs:: $(TARGETS)