I did this:
--- stdint_.h 2007-03-08 08:14:55.000000000 -0800
+++ ../../m4-1.4.8b-orig/lib/stdint_.h 2007-03-01 08:48:39.000000000 -0800
@@ -120,17 +120,12 @@
#define int32_t int
#define uint32_t unsigned int
+#undef int64_t
#if LONG_MAX >> 31 >> 31 == 1
-# undef int64_t
-# define GNULIB_int64_t
# define int64_t long int
#elif defined _MSC_VER
-# undef int64_t
-# define GNULIB_int64_t
# define int64_t __int64
#elif @HAVE_LONG_LONG_INT@
-# undef int64_t
-# define GNULIB_int64_t
# define int64_t long long int
#endif
@@ -169,10 +164,10 @@
#define uint_least16_t uint16_t
#define int_least32_t int32_t
#define uint_least32_t uint32_t
-#ifdef GNULIB_int64_t
+#ifdef int64_t
# define int_least64_t int64_t
#endif
-#ifdef GNULIB_uint64_t
+#ifdef uint64_t
# define uint_least64_t uint64_t
#endif
@@ -200,7 +195,7 @@
#define uint_fast16_t unsigned int_fast16_t
#define int_fast32_t long int
#define uint_fast32_t unsigned int_fast32_t
-#ifdef GNULIB_int64_t
+#ifdef int64_t
# define int_fast64_t int64_t
#endif
#ifdef uint64_t
@@ -222,7 +217,7 @@
#undef intmax_t
#if @HAVE_LONG_LONG_INT@ && LONG_MAX >> 30 == 1
# define intmax_t long long int
-#elif defined GNULIB_int64_t
+#elif defined int64_t
# define intmax_t int64_t
#else
# define intmax_t long int
@@ -269,7 +264,7 @@
#undef INT64_MIN
#undef INT64_MAX
-#ifdef GNULIB_int64_t
+#ifdef int64_t
# define INT64_MIN (~ INT64_MAX)
# define INT64_MAX INTMAX_C (9223372036854775807)
#endif
@@ -308,7 +303,7 @@
#undef INT_LEAST64_MIN
#undef INT_LEAST64_MAX
-#ifdef GNULIB_int64_t
+#ifdef int64_t
# define INT_LEAST64_MIN INT64_MIN
# define INT_LEAST64_MAX INT64_MAX
#endif
@@ -347,7 +342,7 @@
#undef INT_FAST64_MIN
#undef INT_FAST64_MAX
-#ifdef GNULIB_int64_t
+#ifdef int64_t
# define INT_FAST64_MIN INT64_MIN
# define INT_FAST64_MAX INT64_MAX
#endif
@@ -474,7 +469,7 @@
#undef INTMAX_C
#if @HAVE_LONG_LONG_INT@ && LONG_MAX >> 30 == 1
# define INTMAX_C(x) x##LL
-#elif defined GNULIB_int64_t
+#elif defined int64_t
# define INTMAX_C(x) INT64_C(x)
#else
# define INTMAX_C(x) x##L
...and I'm waiting to see if it works (did I mention this box is
god-awful slow? :-)).