m4 didn't work with files in FAT system on Mac OS

[光先邹]

hi,

  If the project was placed in FAT system,

  1. run aclocal will not generate aclocal.m4

  2. run auto header will output 

      error: AC_CONFIG_HEADERS not found in

% echo $M4

/Users/zouguangxian/tmp/m4-1.4.17/src/m4

% autoheader 

autoheader: error: AC_CONFIG_HEADERS not found in configure.in

% head autom4te.cache/traces.0

%

The reason is st_ino of empty file in FAT system is 999999999, which will lead debug set back to stdout in function debug_set_file. Here is a patch which will resolve this problem.

% diff -u  m4-1.4.17.orig/src/debug.c m4-1.4.17/src/debug.c

--- m4-1.4.17.orig/src/debug.c 2013-09-22 13:50:43.000000000 +0800

+++ m4-1.4.17/src/debug.c 2014-05-01 11:55:41.000000000 +0800

@@ -23,6 +23,8 @@

#include <stdarg.h>

#include <sys/stat.h>

+#include <sys/param.h>

+#include <sys/mount.h>

/* File for debugging output.  */

FILE *debug = NULL;

@@ -151,6 +153,20 @@

          && stdout_stat.st_dev == debug_stat.st_dev

          && stdout_stat.st_ino != 0)

        {

+          /* on fat file systems, zero-length files share this magic value */

+          if(debug_stat.st_ino == 999999999) 

+          {

+            struct statfs sfsb;

+            if(fstatfs(fileno (debug), &sfsb) == 0) 

+            {

+              if (strcasecmp(sfsb.f_fstypename, "msdos") == 0 

+                  || strcasecmp(sfsb.f_fstypename, "exfat") == 0) 

+              {

+                return;

+              }

+            }

+          }

+

          if (debug != stderr && close_stream (debug) != 0)

            {

              M4ERROR ((warning_status, errno,

—

Zou Guangxian