$OpenBSD$

index 29ec13f..045a335 100755
--- mach.orig	Fri Feb 20 15:40:37 2015
+++ mach	Fri Feb 20 15:40:37 2015
@@ -1,8 +1,14 @@
-#!/usr/bin/env python
+#!/bin/sh
 # This Source Code Form is subject to the terms of the Mozilla Public
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
+# The beginning of this script is both valid shell and valid python,
+# such that the script starts with the shell and is reexecuted with
+# the right python.
+'''which' python2.7 > /dev/null && exec python2.7 "$0" "$@" || exec python "$0" "$@"
+'''
+
 from __future__ import print_function, unicode_literals
 
 import os
@@ -20,6 +26,15 @@ def load_mach(topsrcdir):
     import mach_bootstrap
     return mach_bootstrap.bootstrap(topsrcdir)
 
+
+def check_and_run_mach(dir_path, args):
+    # If we find the mach bootstrap module, we are in the srcdir.
+    mach_path = os.path.join(dir_path, 'build/mach_bootstrap.py')
+    if os.path.isfile(mach_path):
+        mach = load_mach(dir_path)
+        sys.exit(mach.run(args))
+
+
 def main(args):
     # Check whether the current directory is within a mach src or obj dir.
     for dir_path in ancestors(os.getcwd()):
@@ -41,15 +56,15 @@ def main(args):
                 # Continue searching for mach_bootstrap in the source directory.
                 dir_path = info['topsrcdir']
 
-        # If we find the mach bootstrap module, we are in the srcdir.
-        mach_path = os.path.join(dir_path, 'build/mach_bootstrap.py')
-        if os.path.isfile(mach_path):
-            mach = load_mach(dir_path)
-            sys.exit(mach.run(args[1:]))
+        check_and_run_mach(dir_path, args)
+
+    # If we didn't find a source path by scanning for a mozinfo.json, check
+    # whether the directory containing this script is a source directory.
+    check_and_run_mach(os.path.dirname(__file__), args)
 
     print('Could not run mach: No mach source directory found.')
     sys.exit(1)
 
 
 if __name__ == '__main__':
-    main(sys.argv)
+    main(sys.argv[1:])