[patch] fix building with MKPIGZGZIP=yes

[Joachim Henke <free.software%gmx.com@localhost>]

In -current, build.sh fails due to missing zless/zless.1. The attached
patch brings external/zlib/pigz/bin/pigz/Makefile in sync with
usr.bin/gzip/Makefile, which fixes the build.

Best regards,
Jo.

Index: external/zlib/pigz/bin/pigz/Makefile
===================================================================
RCS file: /cvsroot/src/external/zlib/pigz/bin/pigz/Makefile,v
retrieving revision 1.8
diff -u -r1.8 Makefile
--- external/zlib/pigz/bin/pigz/Makefile	15 Jun 2014 17:54:55 -0000	1.8
+++ external/zlib/pigz/bin/pigz/Makefile	7 Apr 2015 10:24:28 -0000
@@ -33,7 +33,8 @@
 		pigz.1 zcat.1 \
 		zdiff.1 zcmp.1 \
 		zgrep.1 zegrep.1 \
-		zgrep.1 zfgrep.1
+		zgrep.1 zfgrep.1 \
+		zmore.1 zless.1
 
 LINKS+=		${BINDIR}/pigz ${BINDIR}/gzip \
 		${BINDIR}/pigz ${BINDIR}/gunzip \
@@ -41,7 +42,8 @@
 		${BINDIR}/pigz ${BINDIR}/zcat \
 		${BINDIR}/zdiff ${BINDIR}/zcmp \
 		${BINDIR}/zgrep ${BINDIR}/zegrep \
-		${BINDIR}/zgrep ${BINDIR}/zfgrep
+		${BINDIR}/zgrep ${BINDIR}/zfgrep \
+		${BINDIR}/zmore ${BINDIR}/zless
 .endif
 
 .include <bsd.prog.mk>