imaxdiv: Fix compilation error on Android. * m4/imaxdiv.m4 (gl_FUNC_IMAXDIV): Set HAVE_IMAXDIV_T to 0 if imaxdiv_t is not defined. * lib/inttypes.in.h (imaxdiv_t): Define if HAVE_IMAXDIV_T, not HAVE_DECL_IMAXDIV, is 0. * m4/inttypes.m4 (gl_INTTYPES_H_DEFAULTS): Initialize HAVE_IMAXDIV_T. * modules/inttypes-incomplete (Makefile.am): Substitute HAVE_IMAXDIV_T.