'realclean' and 'clobber_all' synonymous with 'distclean'. This patch is contributed by Chris Seawood <cls@seawood.org>. r=wtc@netscape.com Modified files: Makefile, Makefile.in, configure, configure.in, config/Makefile.in, config/config.mk, config/rules.mk git-svn-id: svn://10.0.0.236/trunk@63171 18797224-902f-48f8-a5cc-f745e15eee43