zbar.recipe: Don't pass CPPFLAGS at all
zbar.recipe: Don't pass CPPFLAGS at all

Now that we explicitly set CPPFLAGS, this was failing to build
because it incorrectly passes CPPFLAGS instead of RCFLAGS to WINDRES.

GStreamer/cerbero,nirbheek/cerbero,GStreamer/cerbero,nirbheek/cerbero,GStreamer/cerbero,GStreamer/cerbero,GStreamer/cerbero,nirbheek/cerbero,nirbheek/cerbero