Bug 438623 - Changes to a def file do not relink the library.

Changes to def files will not force libraries to be rebuilt, so there will no
longer need to be a clobber on windows machines.
r=ted

config/rules.mk

@@ -231,6 +231,7 @@ endif # MOZ_MAPINFO
 
 ifdef DEFFILE
 OS_LDFLAGS += -DEF:$(DEFFILE)
+EXTRA_DEPS += $(DEFFILE)
 endif
 
 ifdef MAPFILE