Use AM_PATH_PYTHON to find Python >= 2.5

On OpenSolaris /usr/bin/python is 2.4; use AM_PATH_PYTHON to find
a newer Python. (The PYTHON environment variable can also be set
before running configure to override the search.)

http://bugzilla.gnome.org/show_bug.cgi?id=578196

configure.ac

@@ -28,6 +28,10 @@ AM_GLIB_GNU_GETTEXT
 AC_PATH_PROG(GCONFTOOL, gconftool-2, no)
 AM_GCONF_SOURCE_2
 
+# Get a value to substitute into gnome-shell.in
+AM_PATH_PYTHON([2.5])
+AC_SUBST(PYTHON)
+
 # We need at least this, since gst_plugin_register_static() was added
 # in 0.10.16, but nothing older than 0.10.21 has been tested.
 GSTREAMER_MIN_VERSION=0.10.16

src/Makefile.am

@@ -16,6 +16,7 @@ gnome-shell: gnome-shell.in
 	    -e "s|@libexecdir[@]|$(libexecdir)|" \
 	    -e "s|@libdir[@]|$(libdir)|" \
 	    -e "s|@pkgdatadir[@]|$(pkgdatadir)|" \
+	    -e "s|@PYTHON[@]|$(PYTHON)|" \
 	    -e "s|@sysconfdir[@]|$(sysconfdir)|" \
 	    $< > $@ && chmod a+x $@
 CLEANFILES += gnome-shell

src/gnome-shell.in

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!@PYTHON@
 
 import atexit
 import optparse