This is now the default since debhelper compat 12:
The build system autoconf no longer explicitly set the --libexecdir
variable and thus relies on the build system default - which should
be /usr/libexec (per FHS 3.0, adopted in Debian Policy 4.1.5).

See: https://manpages.debian.org/bookworm/debhelper/debhelper-compat-upgrade-checklist.7.en.html#v12



Signed-off-by: Dylan Aïssi <dylan.aissi@collabora.com>