Speed up thread startup on MS-Windows.

 src/w32.c (w32_delayed_load): Call DisableThreadLibraryCalls on the
 DLL handle, to speed up thread startup.

1 files changed, 7 insertions, 0 deletions

diff --git a/src/w32.c b/src/w32.c
index 8802e13e71d..1ffb6ec171f 100644
--- a/src/w32.c
+++ b/src/w32.c
@@ -8702,6 +8702,13 @@ w32_delayed_load (Lisp_Object library_id)
                                /* Possibly truncated */
                                ? make_specified_string (name, -1, len, 1)
                                : Qnil);
+                /* This prevents thread start and end notifications
+                   from being sent to the DLL, for every thread we
+                   start.  We don't need those notifications because
+                   threads we create never use any of these DLLs, only
+                   the main thread uses them.  This is supposed to
+                   speed up thread creation.  */
+                DisableThreadLibraryCalls (dll_handle);
                 break;
               }
           }