tools/check-includes: compat with Python 3.7

I thought that 3.8 is enough. But Centos8 CI chokes on the walrus.

diff --git a/tools/check-includes.py b/tools/check-includes.py
index abca2882f0b5894d6672dd19ad77e9c374ae9839..afb957a2e12eb75bc6b52f3d2c429347520f2a88 100755 (executable)
--- a/tools/check-includes.py
+++ b/tools/check-includes.py
@@ -14,7 +14,8 @@ def check_file(filename):
     seen = set()
     good = True
     for n, line in enumerate(open(filename)):
-        if m := re.match(r'^\s*#\s*include\s*[<"](\S*)[>"]', line):
+        m = re.match(r'^\s*#\s*include\s*[<"](\S*)[>"]', line)
+        if m:
             include = m.group(1)
             if include in seen:
                 try: