Whenever a new gcc version is released that introduces new warnings,
this breaks lots of builds on the user's side. This change pushes the
detection of these new warnings a bit back until either a user reports
warnings or developers get the new compiler updates. I think this is a
good tradeoff since release builds are no longer totally broken as soon
as a new compiler version comes out.
Travis still uses -Werror because there we actually want builds to fail.
Uses none of the optional dependencies. This ensures that polybar can
build without any of the supposedly optional dependencies. This would
have detected the cause of the xrm build failure before it was merged
