Index: bfd/archive.c
===================================================================
RCS file: /cvs/src/src/bfd/archive.c,v
retrieving revision 1.58
diff -u -r1.58 archive.c
--- bfd/archive.c	2 Sep 2009 07:18:35 -0000	1.58
+++ bfd/archive.c	8 Sep 2009 20:07:38 -0000
@@ -1295,7 +1295,7 @@
 {
   const char *filename = strrchr (file, '/');
 
-#ifdef HAVE_DOS_BASED_FILE_SYSTEM
+  if (have_dos_based_file_system)
   {
     /* We could have foo/bar\\baz, or foo\\bar, or d:bar.  */
     char *bslash = strrchr (file, '\\');
@@ -1304,11 +1304,13 @@
     if (filename == NULL && file[0] != '\0' && file[1] == ':')
       filename = file + 1;
   }
-#endif
-  if (filename != NULL)
-    filename++;
   else
-    filename = file;
+  {
+    if (filename != NULL)
+      filename++;
+    else
+      filename = file;
+  }
   return filename;
 }
 #endif
@@ -1820,7 +1822,7 @@
   const char *filename = strrchr (pathname, '/');
   size_t maxlen = ar_maxnamelen (abfd);
 
-#ifdef HAVE_DOS_BASED_FILE_SYSTEM
+  if (have_dos_based_file_system)
   {
     /* We could have foo/bar\\baz, or foo\\bar, or d:bar.  */
     char *bslash = strrchr (pathname, '\\');
@@ -1829,7 +1831,6 @@
     if (filename == NULL && pathname[0] != '\0' && pathname[1] == ':')
       filename = pathname + 1;
   }
-#endif
 
   if (filename == NULL)
     filename = pathname;
@@ -1868,7 +1869,7 @@
   const char *filename = strrchr (pathname, '/');
   size_t maxlen = ar_maxnamelen (abfd);
 
-#ifdef HAVE_DOS_BASED_FILE_SYSTEM
+  if (have_dos_based_file_system)
   {
     /* We could have foo/bar\\baz, or foo\\bar, or d:bar.  */
     char *bslash = strrchr (pathname, '\\');
@@ -1878,7 +1879,6 @@
     if (filename == NULL && pathname[0] != '\0' && pathname[1] == ':')
       filename = pathname + 1;
   }
-#endif
 
   if (filename == NULL)
     filename = pathname;
Index: gdb/completer.c
===================================================================
RCS file: /cvs/src/src/gdb/completer.c,v
retrieving revision 1.34
diff -u -r1.34 completer.c
--- gdb/completer.c	25 Mar 2009 10:50:56 -0000	1.34
+++ gdb/completer.c	8 Sep 2009 20:07:45 -0000
@@ -232,13 +232,12 @@
 	  else
 	    break;		/* Hit the end of text.  */
 	}
-#if HAVE_DOS_BASED_FILE_SYSTEM
       /* If we have a DOS-style absolute file name at the beginning of
 	 TEXT, and the colon after the drive letter is the only colon
 	 we found, pretend the colon is not there.  */
-      else if (p < text + 3 && *p == ':' && p == text + 1 + quoted)
+      else if (have_dos_based_file_system
+            && p < text + 3 && *p == ':' && p == text + 1 + quoted)
 	;
-#endif
       else if (*p == ':' && !colon)
 	{
 	  colon = p;
Index: gdb/source.c
===================================================================
RCS file: /cvs/src/src/gdb/source.c,v
retrieving revision 1.103
diff -u -r1.103 source.c
--- gdb/source.c	23 Jul 2009 23:20:00 -0000	1.103
+++ gdb/source.c	8 Sep 2009 20:07:46 -0000
@@ -474,14 +474,20 @@
       /* name is the start of the directory.
 	 p is the separator (or null) following the end.  */
 
-      while (!(IS_DIR_SEPARATOR (*name) && p <= name + 1)	/* "/" */
-#ifdef HAVE_DOS_BASED_FILE_SYSTEM
-      /* On MS-DOS and MS-Windows, h:\ is different from h: */
-	     && !(p == name + 3 && name[1] == ':')		/* "d:/" */
-#endif
-	     && IS_DIR_SEPARATOR (p[-1]))
-	/* Sigh. "foo/" => "foo" */
-	--p;
+      if (have_dos_based_file_system) {
+        while (!(IS_DIR_SEPARATOR (*name) && p <= name + 1)	/* "/" */
+        /* On MS-DOS and MS-Windows, h:\ is different from h: */
+	       && !(p == name + 3 && name[1] == ':')		/* "d:/" */
+	       && IS_DIR_SEPARATOR (p[-1]))
+	  /* Sigh. "foo/" => "foo" */
+	  --p;
+      } else {
+        while (!(IS_DIR_SEPARATOR (*name) && p <= name + 1)	/* "/" */
+        /* On MS-DOS and MS-Windows, h:\ is different from h: */
+	       && IS_DIR_SEPARATOR (p[-1]))
+	  /* Sigh. "foo/" => "foo" */
+	  --p;
+      }
       *p = '\0';
 
       while (p > name && p[-1] == '.')
@@ -514,10 +520,9 @@
 
       if (name[0] == '~')
 	name = tilde_expand (name);
-#ifdef HAVE_DOS_BASED_FILE_SYSTEM
-      else if (IS_ABSOLUTE_PATH (name) && p == name + 2) /* "d:" => "d:." */
+      else if (have_dos_based_file_system
+	    && IS_ABSOLUTE_PATH (name) && p == name + 2) /* "d:" => "d:." */
 	name = concat (name, ".", (char *)NULL);
-#endif
       else if (!IS_ABSOLUTE_PATH (name) && name[0] != '$')
 	name = concat (current_directory, SLASH_STRING, name, (char *)NULL);
       else
Index: gdb/top.c
===================================================================
RCS file: /cvs/src/src/gdb/top.c,v
retrieving revision 1.170
diff -u -r1.170 top.c
--- gdb/top.c	31 Aug 2009 20:18:45 -0000	1.170
+++ gdb/top.c	8 Sep 2009 20:07:47 -0000
@@ -184,6 +184,9 @@
 char *lim_at_start;
 #endif
 
+/* Filesystem type */
+int have_dos_based_file_system = 0;
+
 /* Signal to catch ^Z typed while reading a command: SIGTSTP or SIGCONT.  */
 
 #ifndef STOP_SIGNAL
@@ -676,6 +679,15 @@
 		    value);
 }
 
+static void
+show_dos_based_file_system (struct ui_file *file, int from_tty,
+		       struct cmd_list_element *c, const char *value)
+{
+  fprintf_filtered (file, _("\
+Whether the target has a DOS based file system is \"%s\".\n"),
+		    value);
+}
+
 /* This is like readline(), but it has some gdb-specific behavior.
    gdb may want readline in both the synchronous and async modes during
    a single gdb invocation.  At the ordinary top-level prompt we might
@@ -1630,6 +1642,14 @@
 			    show_history_filename,
 			    &sethistlist, &showhistlist);
 
+  add_setshow_boolean_cmd ("dos_based_file_system", class_support,
+			    &have_dos_based_file_system, _("\
+Set whether the target has a DOS based file system"), _("\
+Show whether the target has a DOS based file system"), _("\
+whether the target has a DOS based file system"), NULL,
+			    show_dos_based_file_system,
+			    &setlist, &showlist);
+
   add_setshow_boolean_cmd ("confirm", class_support, &caution, _("\
 Set whether to confirm potentially dangerous operations."), _("\
 Show whether to confirm potentially dangerous operations."), NULL,
Index: gdb/utils.c
===================================================================
RCS file: /cvs/src/src/gdb/utils.c,v
retrieving revision 1.219
diff -u -r1.219 utils.c
--- gdb/utils.c	18 Aug 2009 16:17:16 -0000	1.219
+++ gdb/utils.c	8 Sep 2009 20:07:49 -0000
@@ -3280,15 +3280,14 @@
   strncpy (dir_name, filename, base_name - filename);
   dir_name[base_name - filename] = '\000';
 
-#ifdef HAVE_DOS_BASED_FILE_SYSTEM
   /* We need to be careful when filename is of the form 'd:foo', which
      is equivalent of d:./foo, which is totally different from d:/foo.  */
-  if (strlen (dir_name) == 2 && isalpha (dir_name[0]) && dir_name[1] == ':')
+  if (have_dos_based_file_system
+   && strlen (dir_name) == 2 && isalpha (dir_name[0]) && dir_name[1] == ':')
     {
       dir_name[2] = '.';
       dir_name[3] = '\000';
     }
-#endif
 
   /* Canonicalize the directory prefix, and build the resulting
      filename. If the dirname realpath already contains an ending
Index: gdb/cli/cli-cmds.c
===================================================================
RCS file: /cvs/src/src/gdb/cli/cli-cmds.c,v
retrieving revision 1.92
diff -u -r1.92 cli-cmds.c
--- gdb/cli/cli-cmds.c	11 Jul 2009 14:04:23 -0000	1.92
+++ gdb/cli/cli-cmds.c	8 Sep 2009 20:07:50 -0000
@@ -357,24 +357,27 @@
   if (chdir (dir) < 0)
     perror_with_name (dir);
 
-#ifdef HAVE_DOS_BASED_FILE_SYSTEM
   /* There's too much mess with DOSish names like "d:", "d:.",
      "d:./foo" etc.  Instead of having lots of special #ifdef'ed code,
      simply get the canonicalized name of the current directory.  */
-  dir = getcwd (gdb_dirbuf, sizeof (gdb_dirbuf));
-#endif
+  if (have_dos_based_file_system)
+    dir = getcwd (gdb_dirbuf, sizeof (gdb_dirbuf));
 
   len = strlen (dir);
   if (IS_DIR_SEPARATOR (dir[len - 1]))
     {
       /* Remove the trailing slash unless this is a root directory
          (including a drive letter on non-Unix systems).  */
-      if (!(len == 1)		/* "/" */
-#ifdef HAVE_DOS_BASED_FILE_SYSTEM
-	  && !(len == 3 && dir[1] == ':') /* "d:/" */
-#endif
-	  )
-	len--;
+      if (have_dos_based_file_system)
+        {
+          if (!(len == 1) /* "/" */ && !(len == 3 && dir[1] == ':') /* "d:/" */)
+	    len--;
+        }
+      else
+        {
+          if (!(len == 1))		/* "/" */
+	    len--;
+        }
     }
 
   dir = savestring (dir, len);
Index: include/filenames.h
===================================================================
RCS file: /cvs/src/src/include/filenames.h,v
retrieving revision 1.5
diff -u -r1.5 filenames.h
--- include/filenames.h	21 Mar 2008 23:40:18 -0000	1.5
+++ include/filenames.h	8 Sep 2009 20:07:52 -0000
@@ -5,7 +5,7 @@
    use forward- and back-slash in path names interchangeably, and
    some of them have case-insensitive file names.
 
-   Copyright 2000, 2001, 2007 Free Software Foundation, Inc.
+   Copyright 2000, 2001, 2007, 2009 Free Software Foundation, Inc.
 
 This file is part of BFD, the Binary File Descriptor library.
 
@@ -30,25 +30,36 @@
 extern "C" {
 #endif
 
-#if defined(__MSDOS__) || defined(_WIN32) || defined(__OS2__) || defined (__CYGWIN__)
+/* Defined in gdb/top.c
+  
+   This determines whether we have
+     as a separator : / or \
+     a prefix [a-z]: or not
+   Replaces HAVE_DOS_BASED_FILE_SYSTEM and FILENAME_PREFIX_LEN.
+  
+   Case sensitive/insensitive file name comparison is *not* influenced by this. */
+
+extern int have_dos_based_file_system;
+
+#define	_isalpha(c) (((c >= 'A') && (c <= 'Z')) || ((c >= 'a') && (c <= 'z')))
+
+#define	IS_DIR_SEPARATOR(c)	\
+		((have_dos_based_file_system) ? \
+		((c == '/') || (c == '\\')) : \
+		(c == '/'))
 
-#ifndef HAVE_DOS_BASED_FILE_SYSTEM
-#define HAVE_DOS_BASED_FILE_SYSTEM 1
+#ifndef FALSE
+#define FALSE 0
+#endif
+#ifndef TRUE
+#define TRUE 1
 #endif
 
-#define IS_DIR_SEPARATOR(c)	((c) == '/' || (c) == '\\')
-/* Note that IS_ABSOLUTE_PATH accepts d:foo as well, although it is
-   only semi-absolute.  This is because the users of IS_ABSOLUTE_PATH
-   want to know whether to prepend the current working directory to
-   a file name, which should not be done with a name like d:foo.  */
-#define IS_ABSOLUTE_PATH(f)	(IS_DIR_SEPARATOR((f)[0]) || (((f)[0]) && ((f)[1] == ':')))
-
-#else  /* not DOSish */
-
-#define IS_DIR_SEPARATOR(c)	((c) == '/')
-#define IS_ABSOLUTE_PATH(f)	(IS_DIR_SEPARATOR((f)[0]))
+#define IS_ABSOLUTE_PATH(f) \
+	((IS_DIR_SEPARATOR(f[0])) ? TRUE : \
+	(have_dos_based_file_system ? (_isalpha(f[0]) && (f[1] == ':')) : FALSE))
 
-#endif /* not DOSish */
+#endif	/* static inline functions */
 
 extern int filename_cmp (const char *s1, const char *s2);
 #define FILENAME_CMP(s1, s2)	filename_cmp(s1, s2)