Merge from gnulib.

m4/inttypes.m4

@@ -10,11 +10,14 @@ dnl Test whether <inttypes.h> is supported or must be substituted.
 AC_DEFUN([gl_INTTYPES_H],
 [
   AC_REQUIRE([gl_STDINT_H])
+  AC_CHECK_HEADERS_ONCE([inttypes.h])
 
   dnl Override <inttypes.h> always, so that the portability warnings work.
   AC_REQUIRE([gl_INTTYPES_H_DEFAULTS])
   gl_CHECK_NEXT_HEADERS([inttypes.h])
 
+  AC_REQUIRE([gl_MULTIARCH])
+
   dnl Ensure that <stdint.h> defines the limit macros, since gnulib's
   dnl <inttypes.h> relies on them.  This macro is only needed when a
   dnl C++ compiler is in use; it has no effect for a C compiler.

m4/strtoumax.m4

@@ -32,6 +32,7 @@ AC_DEFUN([gl_FUNC_STRTOUMAX],
 
 # Prerequisites of lib/strtoumax.c.
 AC_DEFUN([gl_PREREQ_STRTOUMAX], [
+  AC_CHECK_DECLS([strtoull])
   AC_REQUIRE([AC_TYPE_UNSIGNED_LONG_LONG_INT])
   gl_FUNC_STRTOULL
 ])