Xcode 6.x
add $(OBJROOT)/UninstalledProducts/include
to BuildSettings->Header Search Paths
Xcode 7.x
add $(OBJROOT)/UninstalledProducts/$(PLATFORM_NAME)/include
to BuildSettings->Header Search Paths
1.Double click the <multiple values>
and you can add this in.
2.Change $(OBJROOT)/UninstalledProducts/include
to $(OBJROOT)/UninstalledProducts/$(PLATFORM_NAME)/include