make check calls zgrep from zutils

[Antonio Diaz Diaz]

Hello.

While testing Rodrigo's patch for --keep option (which BTW seems to work 
fine), I have noticed a couple problems with "make check" in gzip-1.5.

1) "make check 2>&1 | less" seems to block less because it changes stdin 
buffering to line mode; ENTER must be pressed after every keystroke for 
"less" to notice it.

2) the "help-version" test fails because "make check" wrongly invokes 
programs from zutils installed in /usr/local/bin/. For example in 
test-suite.log I read this:

+ env zcmp zin.gz zin2.gz
zdiff: unrecognized option '--__cmp'
Try 'zdiff --help' for more information.
+ echo FAIL: zcmp
FAIL: zcmp


Best regards,
Antonio.