chore(3p/lisp): import sclf source tarball

Used http://wcp.sdf-eu.org/software/sclf-20150207T213551.tbz (sha256
a231aeecdb9e87c72642292a1e083fffb33e69ec1d34e667326c6c35b8bcc794).
There's no upstream repository nor a release since 2015, so importing
seems to make a lot of sense.

Since we can't subtree making any depot-related changes in a separate CL
to make them more discoverable -- this is only the source import.

Change-Id: Ia51a7f4029dba3abd1eee4eeebcf99aca5c5ba4c
Reviewed-on: https://cl.tvl.fyi/c/depot/+/3376
Tested-by: BuildkiteCI
Reviewed-by: grfn <grfn@gws.fyi>

third_party/lisp/sclf/mp/cmu.lisp

@@ -0,0 +1,115 @@
+;;;
+;;; Code freely lifted from various places with compatible license
+;;; terms.  Most of this code is copyright Gilbert Baumann
+;;; <unk6@rz.uni-karlsruhe.de>.  The bugs are copyright Walter
+;;; C. Pelissero <walter@pelissero.de>.
+;;;
+
+;;; This library is free software; you can redistribute it and/or
+;;; modify it under the terms of the GNU Library General Public
+;;; License as published by the Free Software Foundation; either
+;;; version 2 of the License, or (at your option) any later version.
+;;;
+;;; This library is distributed in the hope that it will be useful,
+;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+;;; Library General Public License for more details.
+;;;
+;;; You should have received a copy of the GNU Library General Public
+;;; License along with this library; if not, write to the 
+;;; Free Software Foundation, Inc., 59 Temple Place - Suite 330, 
+;;; Boston, MA  02111-1307  USA.
+
+(in-package :sclf)
+
+(defun make-lock (&optional name)
+  (mp:make-lock name))
+
+(defun make-recursive-lock (&optional name)
+  (mp:make-lock name :kind :recursive))
+
+(defmacro with-lock-held ((lock &key whostate (wait t) timeout) &body forms)
+  `(mp:with-lock-held (,lock ,(or whostate "Lock Wait")
+			     :wait wait
+			     ,@(when timeout (list :timeout timeout)))
+     ,@forms))
+
+(defmacro with-recursive-lock-held ((lock &key wait timeout) &body forms)
+  `(mp:with-lock-held (,lock
+		       ,@(when wait (list :wait wait))
+		       ,@(when timeout (list :timeout timeout)))
+     ,@forms))
+
+(defstruct condition-variable
+  (lock (make-lock "condition variable"))
+  (value nil)
+  (process-queue nil))
+
+(defun %release-lock (lock) ; copied from with-lock-held in multiproc.lisp
+  #+i486 (kernel:%instance-set-conditional
+	  lock 2 mp:*current-process* nil)
+  #-i486 (when (eq (lock-process lock) mp:*current-process*)
+	   (setf (lock-process lock) nil)))
+
+(defun condition-wait (cv lock &optional timeout)
+  (declare (ignore timeout))		;For now
+  (loop
+     (let ((cv-lock (condition-variable-lock cv)))
+       (with-lock-held (cv-lock)
+	 (when (condition-variable-value cv)
+	   (setf (condition-variable-value cv) nil)
+	   (return-from condition-wait t))
+	 (setf (condition-variable-process-queue cv)
+	       (nconc (condition-variable-process-queue cv)
+		      (list mp:*current-process*)))
+	 (%release-lock lock))
+       (mp:process-add-arrest-reason mp:*current-process* cv)
+       (let ((cv-val nil))
+	 (with-lock-held (cv-lock)
+	   (setq cv-val (condition-variable-value cv))
+	   (when cv-val
+	     (setf (condition-variable-value cv) nil)))
+	 (when cv-val
+	   (mp::lock-wait lock "waiting for condition variable lock")
+	   (return-from condition-wait t))))))
+
+(defun condition-notify (cv)
+  (with-lock-held ((condition-variable-lock cv))
+    (let ((proc (pop (condition-variable-process-queue cv))))
+      ;; The waiting process may have released the CV lock but not
+      ;; suspended itself yet
+      (when proc
+	(loop
+	 for activep = (mp:process-active-p proc)
+	 while activep
+	 do (mp:process-yield))
+	(setf (condition-variable-value cv) t)
+	(mp:process-revoke-arrest-reason proc cv))))
+  ;; Give the other process a chance
+  (mp:process-yield))
+
+(defun process-execute (process function)
+  (mp:process-preset process function)
+  ;; For some obscure reason process-preset doesn't make the process
+  ;; runnable.  I'm sure it's me who didn't understand how
+  ;; multiprocessing works under CMUCL, despite the vast documentation
+  ;; available.
+  (mp:enable-process process)
+  (mp:process-add-run-reason process :enable))
+
+(defun destroy-process (process)
+  ;; silnetly ignore a process that is trying to destroy itself
+  (unless (eq (mp:current-process)
+	      process)
+    (mp:destroy-process process)))
+
+(defun restart-process (process)
+  (mp:restart-process process)
+  (mp:enable-process process)
+  (mp:process-add-run-reason process :enable))
+
+(defun process-alive-p (process)
+  (mp:process-alive-p process))
+
+(defun process-join (process)
+  (error "PROCESS-JOIN not support under CMUCL."))