Issue 294: Allow to run setup.py from another directory.

--HG--
branch : distribute
extra : rebase_source : 9219c67abb5791b37822fd67c224a537628c54b9

setup.py

@@ -4,6 +4,9 @@ import sys
 import os
 import textwrap
 
+# Allow to run setup.py from another directory.
+os.chdir(os.path.dirname(os.path.abspath(__file__)))
+
 src_root = None
 if sys.version_info >= (3,):
     tmp_src = os.path.join("build", "src")