Re: building ghc-8.4.2 from source: undefined reference to 'mpz_powm_sec'
> You can start by checking whether you have libgmp
ah yes, I was missing the "gmp-static" package (on Fedora)
so the compilation picked up some other gmp version
installed someplace else. (Worse, since I had "gmp-devel",
I think it picked the .so from one place, and .a from another.)
Thanks, and sorry for the noise.