The zgrep manual page states:
"If zgrep is invoked as zegrep or zfgrep then egrep or
fgrep is used instead of grep."
However, gzip-1.2.4a-2.rpm does not create the zfgrep and zegrep symlinks.
Fixed in our Rawhide version of gzip 1.3 (which may or not be available - this
was fixed some time ago)