With clang 3.7.1 on FreeBSD: elements/audioconvert.c:650:12: error: shifting a negative signed value is undefined [-Werror,-Wshift-negative-value] (-32 << 16) + (1 << 15), (-32 << 16) - (1 << 15), ~~~ ^ https://bugzilla.gnome.org/show_bug.cgi?id=760134