OpenMP does not compile on latest devel
https://github.com/nim-lang/Nim/pull/11985 changed the way C symbol are generated.

Arraymancer needs to use exportc to ensure symbol stability while waiting for #9365

Unfortunately {.exportc.} has a codegen regression as well after https://github.com/nim-lang/Nim/pull/11985 with no workaround for the parallel for loop with annotation:

https://github.com/mratsim/Arraymancer/blob/9a79d84c986eba85bc55a719bba18615f6ca540d/src/tensor/backend/openmp.nim#L36-L49

Tracked upstream: https://github.com/nim-lang/Nim/issues/12081