query ghc for the linkerflags for -staticlib?

[Moritz Angermann]

Hi,

when building a library with -staticlib, how can we query ghc to tell us the linker flags,
that would be needed to link the produced library. (e.g. -liconv and -lgmp)?

I tried --print-ld-linker-flags and --print-gcc-linker-flags and found they were broken, as
is specified in #9614.

Also --info does not provide the needed information.

Cheers,
 Moritz