From 545f5d5a8727b41837d69dfbffd66942123be0ff Mon Sep 17 00:00:00 2001
From: Pablo Galindo Salgado <Pablogsal@gmail.com>
Date: Wed, 29 Sep 2021 14:18:33 +0100
Subject: [PATCH] bpo-44394: Ensure libexpat is linked against libm (GH-28617)
 (cherry picked from commit 6c1154b9de29e1c9cd3d05f5289543e5cff73895)

Co-authored-by: Pablo Galindo Salgado <Pablogsal@gmail.com>
---
 setup.py | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/setup.py b/setup.py
index 54d4b942bd5afe..2bb71dde18d378 100644
--- a/setup.py
+++ b/setup.py
@@ -1686,7 +1686,9 @@ def detect_expat_elementtree(self):
                 ('XML_POOR_ENTROPY', '1'),
             ]
             extra_compile_args = []
-            expat_lib = []
+            # bpo-44394: libexpact uses isnan() of math.h and needs linkage
+            # against the libm
+            expat_lib = ['m']
             expat_sources = ['expat/xmlparse.c',
                              'expat/xmlrole.c',
                              'expat/xmltok.c']