Hello,

Today I tried compiling gzip with `CFLAGS = -ggdb3 -Og', which resulted in the following error 

gzip.c: In function 'main':

gzip.c:609:19: error: 'optc' may be used uninitialized in this function [-Werror=maybe-uninitialized]

                   fprintf (stderr, "-%c: ", optc - ENV_OPTION);

After messing around a bit I found that the problem is with the `-Og' flag. With the default `-O2' the compilation is sucessful.

As expected, by initialising the 'optc' variable the error goes away. I'm just not sure if any value is good for the initialisation.

Regards,

Gonçalo Ribeiro