Enabled this new feature with the makefile variable GREP_LIBZ. If
you don't like it, compile with `make GREP_LIBZ='.
grep + zlib has several advantages:
- the shell script zgrep(1) will be basically a one line
exec grep -Z "$@"
- no shell script, no bugs. The current zgrep implementations
have many bugs and some grep options are no supported.
- no shell script, no security risks.
- it is a magnitude faster than a shell script
Also fixed:
0 -> STDIN_FILENO
Close a file descriptor only if the open call was successfully. It does
not hurt for the open(2) function, but the gzclose(3) function
died in free() to free up (not) allocated memory.
