bitbake: compat/utils: Add copy of python multiprocessing pool for pre 2.7.3 issues

python 2.7 shows hangs with issues in its pool implmenetation. Rather than
try and hack around these, add a copy of the working pool implementation
to the compat module from 2.7.3.

(Bitbake rev: c9eb742637131e8dbd526d2ad9b458abea0a2d87)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/bb/utils.py

@@ -839,4 +839,12 @@ def process_profilelog(fn):
     pout.flush()
     pout.close()  
 
+#
+# Work around multiprocessing pool bugs in python < 2.7.3
+#
+def multiprocessingpool(*args, **kwargs):
+    if sys.version_info < (2, 7, 3):
+        return bb.compat.Pool(*args, **kwargs)
+    else:
+        return multiprocessing.pool.Pool(*args, **kwargs)