scons should use python3 in its scripts

Makefile

 all:
 	tar xf scons-3.0.5.tar.gz
+	patch -Np1 -d scons-3.0.5 < scons-3.0.5-python3.patch
 	cd scons-3.0.5 && python3 setup.py install --prefix=/usr --standard-lib --optimize=1 --install-data=/usr/share
 	rm -rf scons-3.0.5

scons-3.0.5-python3.patch

+diff -uNr scons-3.0.5/script/scons scons-3.0.5-python3/script/scons
+--- scons-3.0.5/script/scons	2019-03-27 09:46:32.000000000 +1030
++++ scons-3.0.5-python3/script/scons	2020-03-12 18:26:11.304866706 +1030
+@@ -1,4 +1,4 @@
+-#! /usr/bin/env python
++#! /usr/bin/env python3
+ #
+ # SCons - a Software Constructor
+ #
+diff -uNr scons-3.0.5/script/scons-configure-cache scons-3.0.5-python3/script/scons-configure-cache
+--- scons-3.0.5/script/scons-configure-cache	2019-03-27 09:46:32.000000000 +1030
++++ scons-3.0.5-python3/script/scons-configure-cache	2020-03-12 18:26:11.305866707 +1030
+@@ -1,4 +1,4 @@
+-#! /usr/bin/env python
++#! /usr/bin/env python3
+ #
+ # SCons - a Software Constructor
+ #
+diff -uNr scons-3.0.5/script/sconsign scons-3.0.5-python3/script/sconsign
+--- scons-3.0.5/script/sconsign	2019-03-27 09:46:32.000000000 +1030
++++ scons-3.0.5-python3/script/sconsign	2020-03-12 18:26:11.306866708 +1030
+@@ -1,4 +1,4 @@
+-#! /usr/bin/env python
++#! /usr/bin/env python3
+ #
+ # SCons - a Software Constructor
+ #
+diff -uNr scons-3.0.5/script/scons-time scons-3.0.5-python3/script/scons-time
+--- scons-3.0.5/script/scons-time	2019-03-27 09:46:32.000000000 +1030
++++ scons-3.0.5-python3/script/scons-time	2020-03-12 18:26:11.309866711 +1030
+@@ -1,4 +1,4 @@
+-#!/usr/bin/env python
++#!/usr/bin/env python3
+ #
+ # scons-time - run SCons timings and collect statistics
+ #