Makefile: use compat regex on Solaris

The system regex is either slow or buggy for complex
patterns, like the built-in xfuncname pattern for java
files.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Makefile

@@ -725,6 +725,7 @@ ifeq ($(uname_S),SunOS)
 	NO_MEMMEM = YesPlease
 	NO_MKDTEMP = YesPlease
 	NO_MKSTEMPS = YesPlease
+	NO_REGEX = YesPlease
 	ifeq ($(uname_R),5.7)
 		NEEDS_RESOLV = YesPlease
 		NO_IPV6 = YesPlease