Depending on *.o in the Xcode output dir did not actually result in a
proper dependency. In Xcode5 this didn't matter much, as the effect was
that the build phase was run every time, but in Xcode6 the phase was
skipped. We now depend on the object directory itself, which will get
its modification time updated to match any rebuilt object files.
Change-Id: I8fa6f06c9008c4ce8f7fde7706057ce101bb5727
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@digia.com>
07c0fdfe7a