* path.cc (symlink_check_one): Recognize symlink settings from the mount table.

* path.h: Make PATH_SYMLINK an alias for MOUNT_SYMLINK.
* syscalls.cc (stat_worker): Use extension search mechanism in path_conv to
look for .exe rather than trying to special case it here.
* mount.h: Make MOUNT_SYMLINK a real option.

winsup/cygwin/include/sys/mount.h

@@ -7,7 +7,7 @@ extern "C" {
 
 enum
   {
-    /* MOUNT_SYMLINK = 1, place holder.  Do not use it. */
+    MOUNT_SYMLINK = 1,	/* "mount point" is a symlink */
     MOUNT_BINARY =  2,	/* "binary" format read/writes */
     MOUNT_SYSTEM =  8,	/* mount point came from system table */
     MOUNT_EXEC   = 16,	/* Any file in the mounted directory gets 'x' bit */