[PATCH 08/17] Regex: Remove unnecessary variables.

[Paul Eggert]

Reviewing:

https://sourceware.org/ml/libc-alpha/2017-12/msg00229.html

The changes to posix/regex_internal.c look good, and are in Gnulib here:

https://git.savannah.gnu.org/cgit/gnulib.git/commit/?id=37dd8efe0cd37c5fa3cb6afbf5e5df99cc6308f6

The changes to posix/regexec.c won't work, as the removed variables are used in 
glibc (they are not used in Gawk).