Introjucer "Header Search Paths" blip

My OSX build finds files in /usr/local/include automatically, but for my iOS build I have to manually add that path to the “header search paths” field in the Introjucer for it to find Boost. Why the difference?

I think it’s an Xcode thing rather than anything that the introjucer’s doing. Nowhere in the code do I add usr/local/include, on either platform.