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	5 Sep 2009 09:23:13 -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/main.c
===================================================================
RCS file: /cvs/src/src/gdb/main.c,v
retrieving revision 1.77
diff -u -r1.77 main.c
--- gdb/main.c	27 Aug 2009 21:56:38 -0000	1.77
+++ gdb/main.c	5 Sep 2009 09:23:13 -0000
@@ -67,6 +67,9 @@
 /* GDB datadir, used to store data files.  */
 char *gdb_datadir = 0;
 
+/* Filesystem type */
+int _have_dos_based_file_system = 1;
+
 struct ui_file *gdb_stdout;
 struct ui_file *gdb_stderr;
 struct ui_file *gdb_stdlog;
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	5 Sep 2009 09:23:14 -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/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	5 Sep 2009 09:23:14 -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	5 Sep 2009 09:23:14 -0000
@@ -357,24 +357,26 @@
   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	5 Sep 2009 09:23:15 -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 +30,54 @@
 extern "C" {
 #endif
 
-#if defined(__MSDOS__) || defined(_WIN32) || defined(__OS2__) || defined (__CYGWIN__)
-
-#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 */
+/*
+ * Defined in gdb/main.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;
+
+static inline int _isalpha(int c)
+{ 
+  if (c <= 'Z' && c >= 'A')
+    return TRUE;
+  if (c <= 'z' && c >= 'a')
+    return TRUE;
+  return FALSE;
+}
 
-#define IS_DIR_SEPARATOR(c)	((c) == '/')
-#define IS_ABSOLUTE_PATH(f)	(IS_DIR_SEPARATOR((f)[0]))
+static inline int IS_DIR_SEPARATOR(int c)
+{
+  if (_have_dos_based_file_system) {
+    return (c == '/' || c == '\\');
+  } else {
+    return (c == '/');
+  }
+}
 
-#endif /* not DOSish */
+static inline int IS_ABSOLUTE_PATH(const char *f)
+{
+  if (IS_DIR_SEPARATOR(f[0]))
+    return TRUE;
+  if (_have_dos_based_file_system) {
+    if (_isalpha(f[0]) && f[1] == ':')
+      return TRUE;
+  }
+  return FALSE;
+}
 
 extern int filename_cmp (const char *s1, const char *s2);
 #define FILENAME_CMP(s1, s2)	filename_cmp(s1, s2)