Deprecate AC_TYPE_SIZE_T It's guaranteed by ISO C90. We already had a comment saying we ought to do this. * doc/autoconf.texi: Mark AC_TYPE_SIZE_T as obsolescent. * lib/autoconf/functions.m4 (AC_FUNC_ALLOCA): Stop using AC_TYPE_SIZE_T. * lib/autoconf/types.m4: Mark AC_TYPE_SIZE_T as obsolescent.