What to do if your hadrian build starts failing (supportedLlvmVersion)

[Matthew Pickering]

If you see this message:

Exit code: 1
Stderr:
compiler/llvmGen/LlvmCodeGen/Base.hs:192:36: error:
    • Couldn't match expected type ‘Int’
                  with actual type ‘(Integer, Integer)’
    • In the first argument of ‘LlvmVersion’, namely ‘(7, 0)’
      In the expression: LlvmVersion (7, 0)
      In an equation for ‘supportedLlvmVersion’:
          supportedLlvmVersion = LlvmVersion (7, 0)
    |
192 | supportedLlvmVersion = LlvmVersion sUPPORTED_LLVM_VERSION
    |                                    ^^^^^
)

Then you need to delete the `includes/ghcautoconf.h` file. It is a
file generated by the Make build system.

Cheers,

Matt