My favorite and most used service for developers is the openSUSE Build Service (OBS). This is where I build syslog-ng packages first, before anywhere else. OBS is open source, highly flexible software to build software packages, and the instance at https://build.opensuse.org/ is free to use for anyone to build open source software. Best of all, it supports multiple architectures, including POWER.
Open Build Service Actually the OBS acronym stands for two things.