diff --git a/src/auto/configure b/src/auto/configure
index 7537e93..cc7d2a1 100755
--- a/src/auto/configure
+++ b/src/auto/configure
@@ -8649,14 +8649,16 @@
 rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
 fi
 
-for ac_header in stdarg.h stdlib.h string.h sys/select.h sys/utsname.h \
-	termcap.h fcntl.h sgtty.h sys/ioctl.h sys/time.h sys/types.h termio.h \
-	iconv.h langinfo.h math.h unistd.h stropts.h errno.h \
-	sys/resource.h sys/systeminfo.h locale.h \
-	sys/stream.h termios.h libc.h sys/statfs.h \
-	poll.h sys/poll.h pwd.h utime.h sys/param.h libintl.h \
-	libgen.h util/debug.h util/msg18n.h frame.h \
-	sys/acl.h sys/access.h sys/sysinfo.h wchar.h wctype.h
+for ac_header in stdarg.h stdint.h stdlib.h string.h \
+	sys/select.h sys/utsname.h termcap.h fcntl.h \
+	sgtty.h sys/ioctl.h sys/time.h sys/types.h \
+	termio.h iconv.h inttypes.h langinfo.h math.h \
+	unistd.h stropts.h errno.h sys/resource.h \
+	sys/systeminfo.h locale.h sys/stream.h termios.h \
+	libc.h sys/statfs.h poll.h sys/poll.h pwd.h \
+	utime.h sys/param.h libintl.h libgen.h \
+	util/debug.h util/msg18n.h frame.h sys/acl.h \
+	sys/access.h sys/sysinfo.h wchar.h wctype.h
 do :
   as_ac_Header=`$as_echo "ac_cv_header_$ac_header" | $as_tr_sh`
 ac_fn_c_check_header_mongrel "$LINENO" "$ac_header" "$as_ac_Header" "$ac_includes_default"
@@ -9033,6 +9035,7 @@
 ;;
   esac
 
+
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether time.h and sys/time.h may both be included" >&5
 $as_echo_n "checking whether time.h and sys/time.h may both be included... " >&6; }
 if test "${ac_cv_header_time+set}" = set; then :
@@ -11216,7 +11219,7 @@
 if ac_fn_c_try_run "$LINENO"; then :
   ac_cv_sizeof_int=`cat conftestval`
 else
-  ac_cv_sizeof_int=0
+  as_fn_error "failed to determine sizeof(int)" "$LINENO" 5
 fi
 rm -f core *.core core.conftest.* gmon.out bb.out conftest$ac_exeext \
   conftest.$ac_objext conftest.beam conftest.$ac_ext
@@ -11231,6 +11234,38 @@
 _ACEOF
 
 
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking uint32_t is 32 bits" >&5
+$as_echo_n "checking uint32_t is 32 bits... " >&6; }
+if test "$cross_compiling" = yes; then :
+  as_fn_error "could not compile program using uint32_t." "$LINENO" 5
+else
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+#ifdef HAVE_STDINT_H
+# include <stdint.h>
+#endif
+#ifdef HAVE_INTTYPES_H
+# include <inttypes.h>
+#endif
+main() {
+  uint32_t nr1 = (uint32_t)-1;
+  uint32_t nr2 = (uint32_t)0xffffffffUL;
+  if (sizeof(uint32_t) != 4 || nr1 != 0xffffffffUL || nr2 + 1 != 0) exit(1);
+  exit(0);
+}
+_ACEOF
+if ac_fn_c_try_run "$LINENO"; then :
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: ok" >&5
+$as_echo "ok" >&6; }
+else
+  as_fn_error "WRONG!  uint32_t not defined correctly." "$LINENO" 5
+fi
+rm -f core *.core core.conftest.* gmon.out bb.out conftest$ac_exeext \
+  conftest.$ac_objext conftest.beam conftest.$ac_ext
+fi
+
+
 
 bcopy_test_prog='
 #include "confdefs.h"
diff --git a/src/blowfish.c b/src/blowfish.c
index ee64db6..01e0993 100644
--- a/src/blowfish.c
+++ b/src/blowfish.c
@@ -21,7 +21,7 @@
 #define BF_OFB_LEN  (8*(BF_BLOCK))
 
 typedef union {
-    uint32_t ul[2];
+    UINT32_T ul[2];
     char_u   uc[8];
 } block8;
 
@@ -36,14 +36,14 @@
 # endif
 #endif
 
-static void bf_e_block __ARGS((uint32_t *p_xl, uint32_t *p_xr));
+static void bf_e_block __ARGS((UINT32_T *p_xl, UINT32_T *p_xr));
 static void bf_e_cblock __ARGS((char_u *block));
-static int bf_check_tables __ARGS((uint32_t ipa[18], uint32_t sbi[4][256], uint32_t val));
+static int bf_check_tables __ARGS((UINT32_T ipa[18], UINT32_T sbi[4][256], UINT32_T val));
 static int bf_self_test __ARGS((void));
 
 /* Blowfish code */
-static uint32_t pax[18];
-static uint32_t ipa[18] = {
+static UINT32_T pax[18];
+static UINT32_T ipa[18] = {
     0x243f6a88u, 0x85a308d3u, 0x13198a2eu,
     0x03707344u, 0xa4093822u, 0x299f31d0u,
     0x082efa98u, 0xec4e6c89u, 0x452821e6u,
@@ -52,8 +52,8 @@
     0xb5470917u, 0x9216d5d9u, 0x8979fb1bu
 };
 
-static uint32_t sbx[4][256];
-static uint32_t sbi[4][256] = {
+static UINT32_T sbx[4][256];
+static UINT32_T sbi[4][256] = {
    {0xd1310ba6u, 0x98dfb5acu, 0x2ffd72dbu, 0xd01adfb7u,
     0xb8e1afedu, 0x6a267e96u, 0xba7c9045u, 0xf12c7f99u,
     0x24a19947u, 0xb3916cf7u, 0x0801f2e2u, 0x858efc16u,
@@ -331,10 +331,10 @@
 
     static void
 bf_e_block(p_xl, p_xr)
-    uint32_t *p_xl;
-    uint32_t *p_xr;
+    UINT32_T *p_xl;
+    UINT32_T *p_xr;
 {
-    uint32_t temp, xl = *p_xl, xr = *p_xr;
+    UINT32_T temp, xl = *p_xl, xr = *p_xr;
 
     F1(0) F2(1) F1(2) F2(3) F1(4) F2(5) F1(6) F2(7)
     F1(8) F2(9) F1(10) F2(11) F1(12) F2(13) F1(14) F2(15)
@@ -346,10 +346,10 @@
 #if 0  /* not used */
     static void
 bf_d_block(p_xl, p_xr)
-    uint32_t *p_xl;
-    uint32_t *p_xr;
+    UINT32_T *p_xl;
+    UINT32_T *p_xr;
 {
-    uint32_t temp, xl = *p_xl, xr = *p_xr;
+    UINT32_T temp, xl = *p_xl, xr = *p_xr;
     F1(17) F2(16) F1(15) F2(14) F1(13) F2(12) F1(11) F2(10)
     F1(9) F2(8) F1(7) F2(6) F1(5) F2(4) F1(3) F2(2)
     xl ^= pax[1];
@@ -401,7 +401,7 @@
     char_u *password;
 {
     int      i, j, keypos = 0;
-    uint32_t val, data_l, data_r;
+    UINT32_T val, data_l, data_r;
     char_u   *key;
     int      keylen;
 
@@ -447,12 +447,12 @@
  */
     static int
 bf_check_tables(ipa, sbi, val)
-    uint32_t ipa[18];
-    uint32_t sbi[4][256];
-    uint32_t val;
+    UINT32_T ipa[18];
+    UINT32_T sbi[4][256];
+    UINT32_T val;
 {
     int i, j;
-    uint32_t c = 0;
+    UINT32_T c = 0;
 
     for (i = 0; i < 18; i++)
 	c ^= ipa[i];
@@ -467,7 +467,7 @@
     char_u   plaintxt[8];
     char_u   cryptxt[8];
     char_u   badcryptxt[8]; /* cryptxt when big/little endian is wrong */
-    uint32_t keysum;
+    UINT32_T keysum;
 } struct_bf_test_data;
 
 /*
@@ -493,6 +493,14 @@
     int    i, bn;
     int    err = 0;
     block8 bk;
+    UINT32_T ui = 0xffffffffUL;
+
+    /* We can't simply use sizeof(UINT32_T), it would generate a compiler
+     * warning. */
+    if (ui != 0xffffffffUL || ui + 1 != 0) {
+	err++;
+	EMSG(_("E820: sizeof(uint32_t) != 4"));
+    }
 
     if (!bf_check_tables(ipa, sbi, 0x6ffa520a))
 	err++;
diff --git a/src/config.h.in b/src/config.h.in
index c5f70fc..c57cd2f 100644
--- a/src/config.h.in
+++ b/src/config.h.in
@@ -216,6 +216,7 @@
 #undef HAVE_FCNTL_H
 #undef HAVE_FRAME_H
 #undef HAVE_ICONV_H
+#undef HAVE_INTTYPES_H
 #undef HAVE_LANGINFO_H
 #undef HAVE_LIBC_H
 #undef HAVE_LIBGEN_H
@@ -228,6 +229,7 @@
 #undef HAVE_PWD_H
 #undef HAVE_SETJMP_H
 #undef HAVE_SGTTY_H
+#undef HAVE_STDINT_H
 #undef HAVE_STRINGS_H
 #undef HAVE_STROPTS_H
 #undef HAVE_SYS_ACCESS_H
diff --git a/src/configure.in b/src/configure.in
index 72138f7..0068d34 100644
--- a/src/configure.in
+++ b/src/configure.in
@@ -2174,14 +2174,16 @@
 		AC_MSG_RESULT(no))
 fi
 
-AC_CHECK_HEADERS(stdarg.h stdlib.h string.h sys/select.h sys/utsname.h \
-	termcap.h fcntl.h sgtty.h sys/ioctl.h sys/time.h sys/types.h termio.h \
-	iconv.h langinfo.h math.h unistd.h stropts.h errno.h \
-	sys/resource.h sys/systeminfo.h locale.h \
-	sys/stream.h termios.h libc.h sys/statfs.h \
-	poll.h sys/poll.h pwd.h utime.h sys/param.h libintl.h \
-	libgen.h util/debug.h util/msg18n.h frame.h \
-	sys/acl.h sys/access.h sys/sysinfo.h wchar.h wctype.h)
+AC_CHECK_HEADERS(stdarg.h stdint.h stdlib.h string.h \
+	sys/select.h sys/utsname.h termcap.h fcntl.h \
+	sgtty.h sys/ioctl.h sys/time.h sys/types.h \
+	termio.h iconv.h inttypes.h langinfo.h math.h \
+	unistd.h stropts.h errno.h sys/resource.h \
+	sys/systeminfo.h locale.h sys/stream.h termios.h \
+	libc.h sys/statfs.h poll.h sys/poll.h pwd.h \
+	utime.h sys/param.h libintl.h libgen.h \
+	util/debug.h util/msg18n.h frame.h sys/acl.h \
+	sys/access.h sys/sysinfo.h wchar.h wctype.h)
 
 dnl sys/ptem.h depends on sys/stream.h on Solaris
 AC_CHECK_HEADERS(sys/ptem.h, [], [],
@@ -2247,6 +2249,7 @@
 AC_TYPE_SIZE_T
 AC_TYPE_UID_T
 AC_TYPE_UINT32_T
+
 AC_HEADER_TIME
 AC_CHECK_TYPE(ino_t, long)
 AC_CHECK_TYPE(dev_t, unsigned)
@@ -2975,11 +2978,30 @@
   exit(0);
 }],
 	    ac_cv_sizeof_int=`cat conftestval`,
-	    ac_cv_sizeof_int=0,
-	    AC_MSG_ERROR(failed to compile test program))])
+	    AC_MSG_ERROR([failed to determine sizeof(int)]),
+	    AC_MSG_ERROR([failed to compile test program]))])
 AC_MSG_RESULT($ac_cv_sizeof_int)
 AC_DEFINE_UNQUOTED(SIZEOF_INT, $ac_cv_sizeof_int)
 
+dnl Make sure that uint32_t is really 32 bits unsigned.
+AC_MSG_CHECKING([uint32_t is 32 bits])
+AC_TRY_RUN([
+#ifdef HAVE_STDINT_H
+# include <stdint.h>
+#endif
+#ifdef HAVE_INTTYPES_H
+# include <inttypes.h>
+#endif
+main() {
+  uint32_t nr1 = (uint32_t)-1;
+  uint32_t nr2 = (uint32_t)0xffffffffUL;
+  if (sizeof(uint32_t) != 4 || nr1 != 0xffffffffUL || nr2 + 1 != 0) exit(1);
+  exit(0);
+}],
+AC_MSG_RESULT(ok),
+AC_MSG_ERROR([WRONG!  uint32_t not defined correctly.]),
+AC_MSG_ERROR([could not compile program using uint32_t.]))
+
 dnl Check for memmove() before bcopy(), makes memmove() be used when both are
 dnl present, fixes problem with incompatibility between Solaris 2.4 and 2.5.
 
diff --git a/src/netbeans.c b/src/netbeans.c
index e058f9e..93a9aea 100644
--- a/src/netbeans.c
+++ b/src/netbeans.c
@@ -43,12 +43,6 @@
 # define sock_close(sd) closesocket(sd)
 # define sleep(t) Sleep(t*1000) /* WinAPI Sleep() accepts milliseconds */
 #else
-  /* uint32_t may be defined by configure, but netdb.h indirectly includes
-   * stdint.h which tries to typedef uint32_t and fails. */
-# ifdef uint32_t
-#  undef uint32_t
-#  undef __uint32_t_defined
-# endif
 # include <netdb.h>
 # include <netinet/in.h>
 # include <sys/socket.h>
diff --git a/src/sha256.c b/src/sha256.c
index de3211a..9372d5f 100644
--- a/src/sha256.c
+++ b/src/sha256.c
@@ -23,14 +23,14 @@
 #ifdef FEAT_CRYPT
 
 typedef struct {
-  uint32_t total[2];
-  uint32_t state[8];
+  UINT32_T total[2];
+  UINT32_T state[8];
   char_u   buffer[64];
 } context_sha256_T;
 
 static void sha256_starts __ARGS((context_sha256_T *ctx));
 static void sha256_process __ARGS((context_sha256_T *ctx, char_u data[64]));
-static void sha256_update __ARGS((context_sha256_T *ctx, char_u *input, uint32_t length));
+static void sha256_update __ARGS((context_sha256_T *ctx, char_u *input, UINT32_T length));
 static void sha256_finish __ARGS((context_sha256_T *ctx, char_u digest[32]));
 static char_u *sha256_bytes __ARGS((char_u *buf, int buflen));
 static unsigned int get_some_time __ARGS((void));
@@ -38,10 +38,10 @@
 
 #define GET_UINT32(n, b, i)		    \
 {					    \
-    (n) = ( (uint32_t)(b)[(i)	 ] << 24)   \
-	| ( (uint32_t)(b)[(i) + 1] << 16)   \
-	| ( (uint32_t)(b)[(i) + 2] <<  8)   \
-	| ( (uint32_t)(b)[(i) + 3]	);  \
+    (n) = ( (UINT32_T)(b)[(i)	 ] << 24)   \
+	| ( (UINT32_T)(b)[(i) + 1] << 16)   \
+	| ( (UINT32_T)(b)[(i) + 2] <<  8)   \
+	| ( (UINT32_T)(b)[(i) + 3]	);  \
 }
 
 #define PUT_UINT32(n,b,i)		  \
@@ -74,8 +74,8 @@
     context_sha256_T *ctx;
     char_u	     data[64];
 {
-    uint32_t temp1, temp2, W[64];
-    uint32_t A, B, C, D, E, F, G, H;
+    UINT32_T temp1, temp2, W[64];
+    UINT32_T A, B, C, D, E, F, G, H;
 
     GET_UINT32(W[0],  data,  0);
     GET_UINT32(W[1],  data,  4);
@@ -207,9 +207,9 @@
 sha256_update(ctx, input, length)
     context_sha256_T *ctx;
     char_u	     *input;
-    uint32_t	     length;
+    UINT32_T	     length;
 {
-    uint32_t left, fill;
+    UINT32_T left, fill;
 
     if (length == 0)
 	return;
@@ -255,8 +255,8 @@
     context_sha256_T *ctx;
     char_u           digest[32];
 {
-    uint32_t last, padn;
-    uint32_t high, low;
+    UINT32_T last, padn;
+    UINT32_T high, low;
     char_u   msglen[8];
 
     high = (ctx->total[0] >> 29) | (ctx->total[1] <<  3);
diff --git a/src/vim.h b/src/vim.h
index 60eae84..d320d3a 100644
--- a/src/vim.h
+++ b/src/vim.h
@@ -32,10 +32,6 @@
 # include "auto/config.h"
 # define HAVE_PATHDEF
 
-/* Avoid a problem when stdint.h gets included later, autoconf defines
- * uint32_t when it is not typedef'ed. */
-# define __uint32_t_defined
-
 /*
  * Check if configure correctly managed to find sizeof(int).  If this failed,
  * it becomes zero.  This is likely a problem of not being able to run the
@@ -52,6 +48,20 @@
 # if defined(__CYGWIN32__) && defined(HAVE_FCHDIR)
 #  undef HAVE_FCHDIR
 # endif
+
+/* We may need to define the uint32_t on non-Unix system, but using the same
+ * identifier causes conflicts.  Therefore use UINT32_T. */
+# define UINT32_T uint32_t
+#endif
+
+#if !defined(UINT32_T)
+# if defined(uint32_t)  /* this doesn't catch typedefs, unfortunately */
+#  define UINT32_T uint32_t
+# else
+  /* Fall back to assuming unsigned int is 32 bit.  If this is wrong then the
+   * test in blowfish.c will fail. */
+#  define UINT32_T unsigned int
+# endif
 #endif
 
 /* user ID of root is usually zero, but not for everybody */
@@ -474,6 +484,12 @@
 
 #include <assert.h>
 
+#ifdef HAVE_STDINT_H
+# include <stdint.h>
+#endif
+#ifdef HAVE_INTTYPES_H
+# include <inttypes.h>
+#endif
 #ifdef HAVE_WCTYPE_H
 # include <wctype.h>
 #endif
@@ -1984,12 +2000,6 @@
 
 #endif
 
-#if !defined(HAVE_CONFIG_H) && !defined(uint32_t) \
-	&& (defined(__CYGWIN32__) || defined(__MINGW32__))
-  /* Assuming that MingW and Cygwin do not typedef uint32_t. */
-# define uint32_t unsigned int
-#endif
-
 /* ISSYMLINK(mode) tests if a file is a symbolic link. */
 #if (defined(S_IFMT) && defined(S_IFLNK)) || defined(S_ISLNK)
 # define HAVE_ISSYMLINK
@@ -2075,13 +2085,6 @@
 #  undef bool
 # endif
 
-/* uint32_t may be defined by configure, but perh.h may indirectly include
- * stdint.h which tries to typedef uint32_t and fails. */
-# ifdef uint32_t
-#  undef uint32_t
-#  undef __uint32_t_defined
-# endif
-
 # ifdef __BORLANDC__
   /* Borland has the structure stati64 but not _stati64 */
 #  define _stati64 stati64