Honoring TMP and TEMP enivironment variables in tmpdir.c

[Juan Manuel Guerrero]

I would like to suggest a small patch to improve support of tmpdir.c for
non-posix systems compilers like djgpp and other win32 compiler except cygwin.
For binaries produced by djgpp and similars that run on Windows/DOS it cannot
be assumed that the TMPDIR environment variable is set.  Usualy it is not set
at all but the TMP and/or TEMP environment variables are almost certainly set.
In the case that those are also not set and the compiler does not provide a
P_tmpdir value then "./" will be used as tmpdir.  This patch would make porting
gnu code a little bit easier.
Comments, objections, suggestions are welcome.

Regards,
Juan M. Guerrero



Index: gnulib/lib/tmpdir.c
===================================================================
RCS file: /sources/gnulib/gnulib/lib/tmpdir.c,v
retrieving revision 1.4
diff -U 4 -r1.4 tmpdir.c
--- gnulib/lib/tmpdir.c 1 Nov 2006 03:46:10 -0000       1.4
+++ gnulib/lib/tmpdir.c 6 Feb 2010 23:21:33 -0000
@@ -54,11 +54,18 @@
  */
 #if defined _WIN32 || defined __WIN32__ || defined __CYGWIN__ || defined 
__EMX__ || defined __DJGPP__
   /* Win32, Cygwin, OS/2, DOS */
 # define ISSLASH(C) ((C) == '/' || (C) == '\\')
+# if defined __CYGWIN__
+   /* Cygwin does not honor TEMP nor TMP */
+#  define HAVE_DIFFERENT_TMPDIRS  0
+# else
+#  define HAVE_DIFFERENT_TMPDIRS  1
+# endif
 #else
   /* Unix */
 # define ISSLASH(C) ((C) == '/')
+# define HAVE_DIFFERENT_TMPDIRS  0
 #endif
 
 
 /* Return nonzero if DIR is an existent directory.  */
@@ -98,8 +105,14 @@
     {
       d = __secure_getenv ("TMPDIR");
       if (d != NULL && direxists (d))
        dir = d;
+#if HAVE_DIFFERENT_TMPDIRS
+      else if ((d = __secure_getenv ("TMP")) && direxists (d))
+       dir = d;
+      else if ((d = __secure_getenv ("TEMP")) && direxists (d))
+       dir = d;
+#endif
       else if (dir != NULL && direxists (dir))
        /* nothing */ ;
       else
        dir = NULL;
@@ -107,10 +120,15 @@
   if (dir == NULL)
     {
       if (direxists (P_tmpdir))
        dir = P_tmpdir;
+#if !HAVE_DIFFERENT_TMPDIRS
       else if (strcmp (P_tmpdir, "/tmp") != 0 && direxists ("/tmp"))
        dir = "/tmp";
+#else
+      else if (strcmp (P_tmpdir, ".") != 0 && direxists ("."))
+       dir = "./";
+#endif
       else
        {
          __set_errno (ENOENT);
          return -1;