Your package fails to build with the newest upcoming autoconf-2.71, which is part of a wide Fedora change. Please see the attached copr: https://copr.fedorainfracloud.org/coprs/odubaj/autoconf-2.70/packages/. More information about testing your package when building with autoconf available here: https://fedoraproject.org/wiki/Changes/Autoconf_271#How_To_Test
Gentle ping.
It doesn't look like autoconf 2.71 is the issue, rather it's the Werror usage in conjuction with g_memdup deprecation in glib 2.68 that makes build fail for me.
Werror should probably be disabled in spec build, in the meantime the related fix is upstream: https://gitlab.freedesktop.org/spice/linux/vd_agent/-/merge_requests/35