Merge branch 'concurrency'

Conflicts (resolved):
	configure.ac
	src/Makefile.in
	src/alloc.c
	src/bytecode.c
	src/emacs.c
	src/eval.c
	src/lisp.h
	src/process.c
	src/regex.c
	src/regex.h

1 files changed, 14 insertions, 0 deletions

diff --git a/lisp/subr.el b/lisp/subr.el
index 5da5bf8388a..1502bed3e4d 100644
--- a/lisp/subr.el
+++ b/lisp/subr.el
@@ -4952,6 +4952,20 @@ as a list.")
           "-pkg.el"))
 
 
+;;; Thread support.
+
+(defmacro with-mutex (mutex &rest body)
+  "Invoke BODY with MUTEX held, releasing MUTEX when done.
+This is the simplest safe way to acquire and release a mutex."
+  (declare (indent 1) (debug t))
+  (let ((sym (make-symbol "mutex")))
+    `(let ((,sym ,mutex))
+       (mutex-lock ,sym)
+       (unwind-protect
+	   (progn ,@body)
+	 (mutex-unlock ,sym)))))
+
+
 ;;; Misc.
 
 (defvar definition-prefixes (make-hash-table :test 'equal)