Compiler error when using Stitcher under iOS

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Whenever I try to use the stitcher class in iOS and I include the stitcher-header ( #include <opencv2/stitching/stitcher.hpp>) I end up with a compile error "Expected '{'" in exposure_compensate.hpp. Apparently the line enum { NO, GAIN, GAIN_BLOCKS }; is causing some sort of error.

I am very new to openCV but using other functions like filter2d() work as expected. How can I resolve this?