Update after gnulib changed.
* autogen.sh: Don't copy intl.m4.
* Makefile.am (distcheck-hook): Don't check glibc2.m4, glibc21.m4, intdiv0.m4,
intl.m4, intmax.m4, printf-posix.m4, uintmax_t.m4, visibility.m4.
* gettext-runtime/intl/verify.h: Update from gnulib.
