[glib] meson: Substitute the Python shebang

[Emmanuele Bassi <ebassi src gnome org>]

commit 0f18a2ebda4ec0440ec545542f9fc2f60cd54c5d
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Fri Jul 14 20:43:19 2017 +0100

    meson: Substitute the Python shebang
    
    Just like we do with Autotools. This allows building glib-mkenums and
    glib-genmarshal on older platforms that only have Python 2.

 gobject/glib-genmarshal.in |    2 +-
 gobject/glib-mkenums.in    |    2 +-
 gobject/meson.build        |    2 ++
 3 files changed, 4 insertions(+), 2 deletions(-)
---
diff --git a/gobject/glib-genmarshal.in b/gobject/glib-genmarshal.in
index 10e0e33..9a39a53 100755
--- a/gobject/glib-genmarshal.in
+++ b/gobject/glib-genmarshal.in
@@ -1,4 +1,4 @@
-#!/usr/bin/env python3
+#!@PYTHON@
 
 # pylint: disable=too-many-lines, missing-docstring, invalid-name
 
diff --git a/gobject/glib-mkenums.in b/gobject/glib-mkenums.in
index 386faf1..6aaef58 100755
--- a/gobject/glib-mkenums.in
+++ b/gobject/glib-mkenums.in
@@ -1,4 +1,4 @@
-#!/usr/bin/env python3
+#!@PYTHON@
 
 # If the code below looks horrible and unpythonic, do not panic.
 #
diff --git a/gobject/meson.build b/gobject/meson.build
index 0953284..ed5ca66 100644
--- a/gobject/meson.build
+++ b/gobject/meson.build
@@ -68,6 +68,7 @@ libgobject_dep = declare_dependency(link_with : libgobject,
 
 glib_mkenums_conf = configuration_data()
 glib_mkenums_conf.set('GLIB_VERSION', glib_version)
+glib_mkenums_conf.set('PYTHON', python.path())
 
 # FIXME: Set permissions
 glib_mkenums = configure_file(input : 'glib-mkenums.in',
@@ -87,6 +88,7 @@ gmarshal_strings = custom_target('gmarshal.strings',
 
 glib_genmarshal_conf = configuration_data()
 glib_genmarshal_conf.set('VERSION', glib_version)
+glib_genmarshal_conf.set('PYTHON', python.path())
 
 glib_genmarshal = configure_file(input : 'glib-genmarshal.in',
   output : 'glib-genmarshal',