Fix bug #12587 with slow startup on MS-Windows with Netlogon service.

 src/fileio.c (check_existing): New function.
 (make_temp_name, Ffile_exists_p, Ffile_writable_p): Call it
 instead of calling 'stat', when what's needed is to check whether
 a file exists.  This avoids expensive system calls on MS-Windows.
 src/w32.c (init_environment): Call 'check_existing' instead of 'stat'.
 src/lread.c (openp) [WINDOWSNT]: Call 'access' instead of 'stat' to
 determine whether a file exists and is not a directory.
 src/lisp.h (check_existing): Add prototype.

1 files changed, 1 insertions, 0 deletions

diff --git a/src/lisp.h b/src/lisp.h
index 62e287561cd..7afe7b373fe 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -3182,6 +3182,7 @@ extern void internal_delete_file (Lisp_Object);
 extern void syms_of_fileio (void);
 extern Lisp_Object make_temp_name (Lisp_Object, bool);
 extern Lisp_Object Qdelete_file;
+extern bool check_existing (const char *);
 
 /* Defined in search.c.  */
 extern void shrink_regexp_cache (void);