nativesdk-gzip: fix reproducibility issues

There is absolute path in zgrep binary. It is related to the changes that fix an
issue with zgrep on Solaris and other platforms with 'grep -e'. We don't have people
building on Solaris.

Original change:
git.savannah.gnu.org/cgit/gzip.git/commit?id=60b3f4eb672a85de28ecaad47ed426f8c8fe6c32

[RP: Tweak commit message]
(From OE-Core rev: fc18ff491111c22c3372c6de21d37945906d2287)

Signed-off-by: Oleh Matiusha <omatiush@cisco.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-extended/gzip/gzip.inc

@@ -8,6 +8,7 @@ inherit autotools texinfo
 export DEFS="NO_ASM"
 
 EXTRA_OEMAKE:class-target = "GREP=${base_bindir}/grep"
+EXTRA_OEMAKE:append:class-nativesdk = " GREP=grep"
 EXTRA_OECONF:append:libc-musl = " gl_cv_func_fflush_stdin=yes "
 
 do_install:append () {