commit 0aab3522b259c40abf1f070c71aa7b914c1239b5
author Miss Islington (bot) <31488909+miss-islington@users.noreply.github.com> Sat Nov 21 22:35:36 2020 -0800
committer GitHub <noreply@github.com> Sun Nov 22 01:35:36 2020 -0500
tree 0869947a29e3cf6c2657969ec5edf0c88b523d2a
parent 4f87126969245861111cc12ca295899944c11b46

bpo-41116: Ensure system supplied libraries are found on macOS 11 (GH-23301) (GH-23455)

On macOS system provided libraries are in a shared library cache
and not at their usual location. This PR teaches distutils to search
in the SDK, even if there was no "-sysroot" argument in
the compiler flags.
(cherry picked from commit 404a719b5127602c1a948f8e189ab61cd3f147d8)

Co-authored-by: Ronald Oussoren <ronaldoussoren@mac.com>

Lib/distutils/unixccompiler.py

diff --git a/Lib/distutils/unixccompiler.py b/Lib/distutils/unixccompiler.py
index 4d7a6de..f0792de 100644
--- a/Lib/distutils/unixccompiler.py
+++ b/Lib/distutils/unixccompiler.py
@@ -290,7 +290,7 @@
             cflags = sysconfig.get_config_var('CFLAGS')
             m = re.search(r'-isysroot\s*(\S+)', cflags)
             if m is None:
-                sysroot = '/'
+                sysroot = _osx_support._default_sysroot(sysconfig.get_config_var('CC'))
             else:
                 sysroot = m.group(1)