building a profiled dynamic exe fails to find libffi_p

With GHC 8.10.7:

I'm trying to profile a big application that uses many shared libraries implemented in haskell (I can't do the usual thing and build a static exe just for profiling).

I started by building GHC and libraries with

GhcLibWays += p_dyn
GhcRTSWays += p_dyn thr_p_dyn

in build.mk.

But linking a test program fails:

$ cat T.hs

main = putStrLn "hej"

$ ./inplace/bin/ghc-stage2 -prof -dynamic --make T.hs -o main
Linking main ...
/usr/bin/ld.gold: error: cannot find -lffi_p
collect2: error: ld returned 1 exit status
`cc' failed in phase `Linker'. (Exit code: 1)

I can manually call cc to link main replacing -lffi_p with -lffi and everything seems to work ok.

I think either we are missing a libffi_p.so or we should link libffi.so.

I've not tried if hadrian does better and provides a libffi_p.so, but I'm not sure if that would be the right solution.