Remove GNU regex.[ch] and use system's regex library. The library is still

GNU regex for now, but will be replaced as soon as an alternative is made
availiable.

bin/expr/Makefile

@@ -1,9 +1,10 @@
 #	/b/source/CVS/src/bin/expr/Makefile,v 1.5 1993/06/14 19:56:06 jtc Exp
 
 PROG=		expr
-SRCS=		expr.c regex.c
-CFLAGS+=	-I${.CURDIR} -DHAVE_STRING_H=1
+SRCS=		expr.c 
 CLEANFILES+=	expr.c y.tab.h
+LDADD+=		-lgnuregex
+DPADD+=		/usr/lib/libgnuregex.a
 
 expr.c:
 	${YACC} -d ${.IMPSRC}