* exceptions.cc (interruptible): Allocate slightly more space for directory

name check.  Windows 95 seems to null-terminate the directory otherwise.
(interrupt_on_return): Issue a fatal error if we can't find the caller's stack.
* spawn.cc (find_exec): Accept a path_conv argument rather than a buffer so
that the caller can find things out about a translated path.
(perhaps_suffix): Ditto.
(spawn_guts): Allocate path_conv stuff here so that we can find out stuff about
the translated path (this is work in progress).
* environ.cc (environ_init): Accept an as-yet unused argument indicating
whether we were invoked from a cygwin parent or not.
(winenv): Ditto.
(posify): Accept an argument indicating whether the path has already been
translated.
* dlfcn.cc (check_access): Provide a path_conv buffer to find_exec.
* exec.cc (sexecvpe): Ditto.
* path.cc (path_conv::check): Rename from path_conv::path_conv.
(mount_item::getmntent): Recognize "Cygwin executable" bit.
(symlink_info::check): Remove debugging statements.
* path.h (class path_conv): Add iscygexec method.  Rewrite constructor to call
"check" method to allow multiple operations on a path_conv variable.
* pinfo.cc (pinfo_init): Pass argument to environ_init.
* shared.h: Bump PROC_MAGIC.
* winsup.h: Reflect above changes to function arguments.
* include/sys/mount.h: Add MOUNT_CYGWIN_EXEC type.

winsup/cygwin/pinfo.cc

@@ -77,7 +77,7 @@ pinfo_init (LPBYTE info)
     {
       /* The process was execed.  Reuse entry from the original
 	 owner of this pid. */
-      environ_init ();	  /* Needs myself but affects calls below */
+      environ_init (0);	  /* Needs myself but affects calls below */
 
       /* spawn has already set up a pid structure for us so we'll use that */
 
@@ -100,7 +100,7 @@ pinfo_init (LPBYTE info)
       myself->ctty = -1;
       myself->uid = USHRT_MAX;
 
-      environ_init ();		/* call after myself has been set up */
+      environ_init (0);		/* call after myself has been set up */
     }
 
   debug_printf ("pid %d, pgid %d", myself->pid, myself->pgid);