Check that one of BUILD_READERS/BUILD_WRITERS is enabled
Check that one of BUILD_READERS/BUILD_WRITERS is enabled

It doesn't make sense to build with both disabled,
since then the library will not do anything.

huycn/zxing-cpp,huycn/zxing-cpp,huycn/zxing-cpp,nu-book/zxing-cpp,nu-book/zxing-cpp,nu-book/zxing-cpp,nu-book/zxing-cpp,huycn/zxing-cpp,huycn/zxing-cpp,huycn/zxing-cpp,huycn/zxing-cpp,nu-book/zxing-cpp,nu-book/zxing-cpp,huycn/zxing-cpp,nu-book/zxing-cpp,nu-book/zxing-cpp