x86_64 dynamic / PIC

I'm trying to get GHC 8.6.3 running on 64-bit Haiku, cross compiling from 32-bit Haiku. (UNIX-like OS, gcc 7.) The build died when it started trying link up 64 bit .dyn_o, with ld.bfd: utils/hsc2hs/dist-install/build/Main.dyn_o: relocation R_X86_64_PC32 can not be used when making a shared object; recompile with -fPIC But it appears to me that gcc is already configured to use -fPIC with cc1. (Both 32 bit and 64 bit cross-compiler.) And so is ghc-stage1. So I suspect the suggested remedy isn't going to get me very far. Anyone have an idea how to proceed? thanks! Donn