Misc warning fixes

Misc warning fixes

glib/pcre/pcre_ucp_search_funcs.c, glib/pcre/pcre_valid_utf8.c: add
back missing config.h includes, and this time add them to the copies
in glib/update-pcre/ too so they don't get lost again on the next PCRE
update.

glib/garray.c, glib/gbase64.c: fix signed/unsigned pointer casts

gio/xdgmime/xdgmimeglob.c: remove unused variable

gio/tests/live-g-file.c: fix printf args on x86_64

tests/Makefile.am, tests/regex-test.c: remove redundant -DENABLE_REGEX