Disable "unused-result" warning in release builds

src/build/Common.gmake

@@ -442,7 +442,7 @@ ifdef DEBUG
 else # RELEASE
  # -finline-functions (used to) break the baja build badly.
  # This also meant that -O3 wouldn't work either.
- CFLAGS	:= -O3 -fomit-frame-pointer -ffast-math -funroll-loops $(CFLAGS)
+ CFLAGS	:= -O3 -Wno-unused-result -fomit-frame-pointer -ffast-math -funroll-loops $(CFLAGS)
 endif
 
 -include targets.mk