Depend on subprocess32 on posix systems for python27

And use it in plase of subprocess on posix systems.

Author: jenshnielsen

lib/matplotlib/compat/subprocess.py

@@ -5,6 +5,8 @@
   2.7 onwards).
 - Provides a stub implementation of subprocess members on Google App Engine
   (which are missing in subprocess).
+- Use subprocess32, backport from python 3.2 on Linux/Mac work-around for
+  https://github.com/matplotlib/matplotlib/issues/5314
 
 Instead of importing subprocess, other modules should use this as follows:
 
@@ -15,8 +17,16 @@
 
 from __future__ import absolute_import    # Required to import subprocess
 from __future__ import print_function
-
-import subprocess
+import os
+import sys
+if os.name == 'posix' and sys.version_info[:2] < (3, 2):
+    # work around for https://github.com/matplotlib/matplotlib/issues/5314
+    try:
+        import subprocess32 as subprocess
+    except ImportError:
+        import subprocess
+else:
+    import subprocess
 
 __all__ = ['Popen', 'PIPE', 'STDOUT', 'check_output', 'CalledProcessError']
 

setup.py

@@ -70,6 +70,7 @@
     setupext.Six(),
     setupext.Dateutil(),
     setupext.FuncTools32(),
+    setupext.Subprocess32(),
     setupext.Pytz(),
     setupext.Cycler(),
     setupext.Tornado(),

setupext.py

@@ -1400,6 +1400,30 @@ def get_install_requires(self):
             return []
 
 
+class Subprocess32(SetupPackage):
+    name = "subprocess32"
+
+    def check(self):
+        if sys.version_info[:2] < (3, 2):
+            try:
+                import subprocess32
+            except ImportError:
+                return (
+                    "subprocess was not found. It is an optional dependency"
+                    " for for python versions prior to 3.2 that improves"
+                    " functionality on Linux and OSX")
+
+            return "using subprocess32"
+        else:
+            return "Not required"
+
+    def get_install_requires(self):
+        if sys.version_info[:2] < (3, 2) and os.name == 'posix':
+            return ['subprocess32']
+        else:
+            return []
+
+
 class Tornado(OptionalPackage):
     name = "tornado"