--- gcc-3.4.6/gcc/cppfiles.c	2013-05-19 20:22:04.000000000 +0200
+++ gcc/cppfiles.c	2013-05-19 20:23:32.000000000 +0200
@@ -50,6 +50,10 @@
 #ifndef O_BINARY
 # define O_BINARY 0
 #endif
+#ifndef OPEN_CASE_SENSITIVE
+/* Default is standard open().  */
+# define OPEN_CASE_SENSITIVE open
+#endif
 
 /* This structure represents a file searched for by CPP, whether it
    exists or not.  An instance may be pointed to by more than one
@@ -210,7 +214,7 @@
       set_stdin_to_binary_mode ();
     }
   else
-    file->fd = open (file->path, O_RDONLY | O_NOCTTY | O_BINARY, 0666);
+    file->fd = OPEN_CASE_SENSITIVE (file->path, O_RDONLY | O_NOCTTY | O_BINARY, 0666);
 
   if (file->fd != -1)
     {
@@ -1109,7 +1113,11 @@
   flen = strlen (fname);
   path = xmalloc (dlen + 1 + flen + 1);
   memcpy (path, dir->name, dlen);
-  if (dlen && path[dlen - 1] != '/')
+  if (dlen
+#ifdef VOL_SEPARATOR
+      && path[dlen - 1] != VOL_SEPARATOR
+#endif
+      && path[dlen - 1] != '/')
     path[dlen++] = '/';
   memcpy (&path[dlen], fname, flen + 1);
 
@@ -1157,7 +1165,11 @@
   len = dir->len;
   name = alloca (len + sizeof (FILE_NAME_MAP_FILE) + 1);
   memcpy (name, dir->name, len);
-  if (len && name[len - 1] != '/')
+  if (len
+#ifdef VOL_SEPARATOR
+      && name[len - 1] != VOL_SEPARATOR
+#endif
+      && name[len - 1] != '/')
     name[len++] = '/';
   strcpy (name + len, FILE_NAME_MAP_FILE);
   f = fopen (name, "r");