Skip tests requiring Perl and less (more).
Also zgrep-signal skipping fails with weird Bad file number error on illumos.
--- gzip-1.5/tests/Makefile.in.orig	2013-02-23 15:15:08.017048868 +0000
+++ gzip-1.5/tests/Makefile.in	2013-02-23 15:15:32.756197039 +0000
@@ -1421,7 +1421,6 @@
   trailing-nul				\
   zdiff					\
   zgrep-f				\
-  zgrep-signal				\
   znew-k
 
 EXTRA_DIST = \
@@ -1441,8 +1440,6 @@
   zfgrep	\
   zforce	\
   zgrep		\
-  zless		\
-  zmore		\
   znew
 
 TESTS_ENVIRONMENT = \