Minimal build option

[nissenhutmark]

Please would you add an option to cmake which only builds static libraries and installs headers, e.g. without requiring ghc. This would address situations where it is not possible to run gbc on the client, e.g. Raspberry Pi with 1GB where the gbc has been run elsewhere and gbc generated code is part of the client's project.

[chwarr]

That makes sense. This sounds like cross-compilation too. Some additional work may be needed in the CMake files to support this. E.g., build gbc targeting x64 and then use that to build the libs targeting arm64.

Feel free to submit a PR to add this support.