Make 'gmake depend' do a 'gmake clean' temporarily, because I am

going to check in a change to the header file _linux.h and NSPR
makefiles don't implement 'gmake depend'.  I must force the
Tinderbox 'gmake depend' continuous builds to rebuild the files
after the header file change.  I really hate to do this hack but...

nsprpub/Makefile

@@ -101,5 +101,5 @@ endif
 	cp -f mdheader.jar $(MDIST)/$(MOD_NAME)/$(BUILD_NUMBER)/$(OBJDIR_NAME); \
 	chmod 664 $(MDIST)/$(MOD_NAME)/$(BUILD_NUMBER)/$(OBJDIR_NAME)/mdheader.jar
 
-depend:
+depend: clean
 	@echo "NSPR20 has no dependencies.  Skipped."