pass back python bin from configure

pylib/gyp/__init__.py

Index: pylib/gyp/__init__.py
diff --git a/pylib/gyp/__init__.py b/pylib/gyp/__init__.py
index 3769c526522e98b52b7139c0fb22e5881a22a69a..736c2fec8a6b293796495a129a108830da3bd15a 100755
--- a/pylib/gyp/__init__.py
+++ b/pylib/gyp/__init__.py
@@ -70,6 +70,9 @@ def Load(build_files, format, default_variables={},
   # avoiding collisions with user and automatic variables.
   default_variables['GENERATOR'] = format
 
+  # Provide a PYTHON value to run sub-commands with the same python
+  default_variables['PYTHON'] = sys.executable

[Mark Mentovai, 2013/03/04 21:24:53]

default_variables isn’t right. Which commands are you interested in having
PYTHON set for? Various ones that might run from within GYP? You’ll want to set
PYTHON in the environment. Commands that might be invoked during a build
(post-GYP)? There’s no guarantee that anything in default_variables gets
exported to the environment.

I don’t think this function is the right spot for this, either. If you’re going
to alter the environment, you probably want to use gyp_main, not Load.

[Evan Martin, 2013/03/05 17:05:49]

(I glanced at the Mozilla patch that prompted this)

They are writing their action commands lines like (sorry for forgetting gyp
syntax):
"<(PYTHON) foo.py <(INPUTS)"
which is why the above works for them.

[tony, 2013/03/05 22:33:24]

Is it possible to use <!@pymod_do_main(foo <@(INPUTS)) to execute code from
foo.py without spawning a new python process? See
https://code.google.com/p/gyp/source/detail?r=924

+
   # Format can be a custom python file, or by default the name of a module
   # within gyp.generator.
   if format.endswith('.py'):