freeswitch-stable: fix incompatible pointer type

freeswitch-stable: fix incompatible pointer type

Currently compiles fail with:

  CC       libfreeswitch_la-switch_regex.lo
src/switch_regex.c: In function 'switch_regex_compile':
src/switch_regex.c:40:9: error: return from incompatible pointer type [-Werror=incompatible-pointer-types]
  return pcre_compile(pattern, options, errorptr, erroroffset, tables);
         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
cc1: all warnings being treated as errors
Makefile:2100: recipe for target 'libfreeswitch_la-switch_regex.lo' failed
make[5]: *** [libfreeswitch_la-switch_regex.lo] Error 1

Fix cherry-picked from upstream.

Signed-off-by: Sebastian Kemper <sebastian_ml@gmx.net>