Make output dir if it doesn't exist.

sphinx/__init__.py

@@ -72,8 +72,8 @@ def main(argv=sys.argv):
             return 1
         outdir = path.abspath(args[1])
         if not path.isdir(outdir):
-            print >>sys.stderr, 'Error: Cannot find output directory.'
-            return 1
+            print >>sys.stderr, 'Making output directory...'
+            os.makedirs(outdir)
     except (IndexError, getopt.error):
         usage(argv)
         return 1

sphinx/builder.py

@@ -67,7 +67,7 @@ class Builder(object):
         self.outdir = app.outdir
         self.doctreedir = app.doctreedir
         if not path.isdir(self.doctreedir):
-            os.mkdir(self.doctreedir)
+            os.makedirs(self.doctreedir)
 
         self.app = app
         self.warn = app.warn