* globals.cc: Improve comment on R/O UNICODE_STRINGs.

* mount.h (class fs_info): Add is_mvfs bit.
	* mount.cc (fs_info::update): Recognize MVFS remote filesystem.
	(fillout_mntent): Reorder filesystem checks for speed.  Add
	mvfs, unixfs, and sunwnfs filesystem types.
	* path.h (class path_conv): Add fs_is_mvfs method.
	* path.cc (symlink_worker): On MVFS, always create symlinks as
	Windows shortcuts.  Explain why.

winsup/cygwin/globals.cc

@@ -72,7 +72,13 @@ char NO_COPY almost_null[1];
 
 char *old_title;
 
-/* Heavily-used const UNICODE_STRINGs are defined here once. */
+/* Heavily-used const UNICODE_STRINGs are defined here once.  The idea is a
+   speed improvement by not having to initialize a UNICODE_STRING every time
+   we make a string comparison.  The strings are not defined as const,
+   because the respective NT functions are not taking const arguments
+   and doing so here results in lots of extra casts for no good reason.
+   Rather, the strings are placed in the R/O section .rdata, so we get
+   a SEGV if some code erroneously tries to overwrite these strings. */
 #define _ROU(_s) \
         { Length: sizeof (_s) - sizeof (WCHAR), \
           MaximumLength: sizeof (_s), \