build-sys: fix compiler warnings to make build more silent
build-sys: fix compiler warnings to make build more silent

heftig/avahi,heftig/avahi,heftig/avahi-1,Distrotech/avahi,everbase/catta,heftig/avahi,gloryleague/avahi,Kisensum/xmDNS-avahi,catta-x/catta,Distrotech/avahi,Distrotech/avahi,heftig/avahi,lathiat/avahi,gloryleague/avahi,lathiat/avahi,Kisensum/xmDNS-avahi,lathiat/avahi,heftig/avahi-1,Kisensum/xmDNS-avahi,Distrotech/avahi,heftig/avahi-1,Distrotech/avahi,gloryleague/avahi,Kisensum/xmDNS-avahi,heftig/avahi-1,lathiat/avahi,Kisensum/xmDNS-avahi,Distrotech/avahi,gloryleague/avahi,heftig/avahi-1,catta-x/catta,everbase/catta,heftig/avahi-1,gloryleague/avahi,gloryleague/avahi,lathiat/avahi,Kisensum/xmDNS-avahi,catta-x/catta,heftig/avahi,lathiat/avahi,everbase/catta,heftig/avahi