use writelines when writing _sysinfo.py

setupbase.py

@@ -389,9 +389,8 b' def record_commit_info(pkg_dir, build_cmd=build_py):'
             # We write the installation commit even if it's empty
             out_pth = pjoin(self.build_lib, pkg_dir, 'utils', '_sysinfo.py')
             with io.open(out_pth, 'w') as out_file:
-                for line in [
-                    u"# GENERATED BY setup.py",
-                    u"commit = '%s'" % repo_commit,
-                ]:
-                    out_file.write(line + u'\n')
+                out_file.writelines([
+                    u"# GENERATED BY setup.py\n",
+                    u"commit = '%s'\n" % repo_commit,
+                ])
     return MyBuildPy