Makefile: default pager on AIX to "more"

AIX doesn't ship with "less" by default, and their "more" is
more featureful than average, so the latter is a more
sensible choice.  People who really want less can set the
compile-time option themselves, or users can set $PAGER.

Signed-off-by: Jeff King <peff@peff.net>
Tested-by: Tor Arntsen <tor@spacetec.no>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Makefile

@@ -886,6 +886,7 @@ ifeq ($(uname_S),NetBSD)
 	NO_MKSTEMPS = YesPlease
 endif
 ifeq ($(uname_S),AIX)
+	DEFAULT_PAGER = more
 	NO_STRCASESTR=YesPlease
 	NO_MEMMEM = YesPlease
 	NO_MKDTEMP = YesPlease