python: fix i686 multiprocessing errors

srcpkgs/python/patches/fix-i686-rlock.patch

@@ -0,0 +1,55 @@
+It seems that avoiding to create local aliases for the self._rlock and
+self._wlock methods prevents the strange errors on i686 related to
+semaphore locking and unlocking.
+
+One example of failing builds is firefox-esr running gyp in an i686 environment.
+
+--- Lib/multiprocessing/queues.py	2017-09-16 19:38:35.000000000 +0200
++++ Lib/multiprocessing/queues.py	2017-10-24 19:49:06.291351206 +0200
+@@ -369,13 +369,11 @@
+ 
+     def _make_methods(self):
+-        recv = self._reader.recv
+-        racquire, rrelease = self._rlock.acquire, self._rlock.release
+         def get():
+-            racquire()
+-            try:
+-                return recv()
+-            finally:
+-                rrelease()
++            self._rlock.acquire()
++            try:
++                return self._reader.recv()
++            finally:
++                self._rlock.release()
+         self.get = get
+ 
+         if self._wlock is None:
+@@ -383,11 +382,9 @@
+             self.put = self._writer.send
+         else:
+-            send = self._writer.send
+-            wacquire, wrelease = self._wlock.acquire, self._wlock.release
+             def put(obj):
+-                wacquire()
+-                try:
+-                    return send(obj)
+-                finally:
+-                    wrelease()
++                self._wlock.acquire()
++                try:
++                    return self._writer.send(obj)
++                finally:
++                    self._wlock.release()
+             self.put = put
+--- Modules/_multiprocessing/semaphore.c	2017-09-16 19:38:35.000000000 +0200
++++ Modules/_multiprocessing/semaphore.c	2017-10-28 10:49:56.944993401 +0200
+@@ -378,7 +378,7 @@
+             }
+         }
+ #else
+-        int sval;
++        int sval = -1;
+ 
+         /* This check is not an absolute guarantee that the semaphore
+            does not rise above maxvalue. */