From 1f0d3e9b001528d4588ec5e028cc58d311187c06 Mon Sep 17 00:00:00 2001
From: Eric Soroos <eric-github@soroos.net>
Date: Wed, 9 Jul 2014 10:12:43 -0700
Subject: [PATCH 1/2] Don't install mp_compile if multiprocessing.Pool() fails,
 or if 1 process is going to be used

---
 mp_compile.py | 28 +++++++++++++++++++---------
 1 file changed, 19 insertions(+), 9 deletions(-)

diff --git a/mp_compile.py b/mp_compile.py
index 71b4089e1..b7c3e7ce4 100644
--- a/mp_compile.py
+++ b/mp_compile.py
@@ -5,6 +5,11 @@ from multiprocessing import Pool, cpu_count
 from distutils.ccompiler import CCompiler
 import os
 
+try:
+    MAX_PROCS = int(os.environ.get('MAX_CONCURRENCY', cpu_count()))
+except:
+    MAX_PROCS = None
+        
 
 # hideous monkeypatching.  but. but. but.
 def _mp_compile_one(tp):
@@ -31,22 +36,27 @@ def _mp_compile(self, sources, output_dir=None, macros=None,
         output_dir, macros, include_dirs, sources, depends, extra_postargs)
     cc_args = self._get_cc_args(pp_opts, debug, extra_preargs)
 
-    try:
-        max_procs = int(os.environ.get('MAX_CONCURRENCY', cpu_count()))
-    except:
-        max_procs = None
-    pool = Pool(max_procs)
+    pool = Pool(MAX_PROCS)
     try:
         print ("Building using %d processes" % pool._processes)
     except:
         pass
-    arr = [
-        (self, obj, build, cc_args, extra_postargs, pp_opts) for obj in objects
-        ]
+    arr = [(self, obj, build, cc_args, extra_postargs, pp_opts)
+           for obj in objects]
     pool.map_async(_mp_compile_one, arr)
     pool.close()
     pool.join()
     # Return *all* object filenames, not just the ones we just built.
     return objects
 
-CCompiler.compile = _mp_compile
+# explicitly don't enable if environment says 1 processor
+if MAX_PROCS != 1:
+    try:
+        # bug, only enable if we can make a Pool. see issue #790 and
+        # http://stackoverflow.com/questions/6033599/oserror-38-errno-38-with-multiprocessing
+        pool = Pool(2)
+        CCompiler.compile = _mp_compile
+    except Exception as msg:
+        print("Exception installing mp_compile, proceeding without: %s" %msg)
+else:
+    print("Single threaded build, not installing mp_compile: %s processes" %MAX_PROCS)

From 919315eb9d55955a1b3cedadcdf111aca7af9762 Mon Sep 17 00:00:00 2001
From: Eric Soroos <eric-github@soroos.net>
Date: Wed, 9 Jul 2014 10:13:02 -0700
Subject: [PATCH 2/2] More agressive make clean

---
 Makefile | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/Makefile b/Makefile
index 0637e901f..3dcfe8d13 100644
--- a/Makefile
+++ b/Makefile
@@ -15,7 +15,9 @@ pre:
 clean:
 	python setup.py clean
 	rm PIL/*.so || true
-	find . -name __pycache__ | xargs rm -r
+	rm -r build || true
+	find . -name __pycache__ | xargs rm -r || true
+
 
 install:
 	python setup.py install