.xcconfig not being used for prefix header

John Brownie

I have been working on changing a C/C++/Objective C app that uses the Nano library so that it uses the LLVM C++ Standard Library rather than the GNU version. After a fair bit of work in Xcode 9, I get it compiling there. However, I have a significant problem when I move to Xcode 10, in that the settings in the .xcconfig files (particularly the header search paths) are not being used when precompiling (or, it seems, compiling) the prefix header.

That is the basis of the problem, but there is another mystery which may be related. In the Nano project, the .xcconfig files are listed in the Levels view between the project and the target, whereas in the main project, they are between the macOS default and the project.

Since the problem manifests in Xcode 10.2.1 and not in Xcode 9.4, I assume that it is the "new build system" that is likely to be the culprit, but there doesn't seem to be enough documentation about it to be sure.

Anybody else have this sort of issue, or know of what I could tweak to get around this?

John Brownie
Mussau-Emira language, New Ireland Province, Papua New Guinea
Kouvola, Finland

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