python: restore previous distutils.sysconfig CFLAGS handling

CFLAGS retrieved via get_config_vars() had been
overwritten in Lib/distutils/sysconfig.py’s
function customize_compiler() when the CFLAGS
environment variable had been set. With 2.7.17
the flags are appended which leads to using host
CFLAGS when cross compiling.

The patch restores the old behaviour.

srcpkgs/python/patches/sysconfig.patch

@@ -0,0 +1,22 @@
+--- Lib/distutils/sysconfig.py	2019-10-19 20:38:44.000000000 +0200
++++ Lib/distutils/sysconfig.py	2019-03-02 19:17:42.000000000 +0100
+@@ -181,8 +171,8 @@
+                 _osx_support.customize_compiler(_config_vars)
+                 _config_vars['CUSTOMIZED_OSX_COMPILER'] = 'True'
+ 
+-        (cc, cxx, cflags, ccshared, ldshared, so_ext, ar, ar_flags) = \
+-            get_config_vars('CC', 'CXX', 'CFLAGS',
++        (cc, cxx, opt, cflags, ccshared, ldshared, so_ext, ar, ar_flags) = \
++            get_config_vars('CC', 'CXX', 'OPT', 'CFLAGS',
+                             'CCSHARED', 'LDSHARED', 'SO', 'AR',
+                             'ARFLAGS')
+ 
+@@ -206,7 +196,7 @@
+         if 'LDFLAGS' in os.environ:
+             ldshared = ldshared + ' ' + os.environ['LDFLAGS']
+         if 'CFLAGS' in os.environ:
+-            cflags = cflags + ' ' + os.environ['CFLAGS']
++            cflags = opt + ' ' + os.environ['CFLAGS']
+             ldshared = ldshared + ' ' + os.environ['CFLAGS']
+         if 'CPPFLAGS' in os.environ:
+             cpp = cpp + ' ' + os.environ['CPPFLAGS']

srcpkgs/python/template

@@ -4,7 +4,7 @@
 #
 pkgname=python
 version=2.7.17
-revision=1
+revision=2
 wrksrc="Python-${version}"
 pycompile_dirs="usr/lib/python2.7"
 hostmakedepends="pkg-config"