Your latest report helped me find another portability problem. 
Ironically, a compatibility feature in Android API 23 intended to make 
it easier porting GNU software by assuming the GNU API for strerror_r, 
collided with a compatibility feature in Gnulib intended to make it 
easier to port GNU software by assuming the POSIX API for strerror_r.

I installed a Gnulib patch to fix that (you should have received email a 
few hours ago), and am attaching a revised gzip tarball. Please give it 
a try.

Thanks again for these reports. They should help make it easier to run 
several GNU programs on Android, not just gzip.