libffi: fix musl tests

Tests do not compile on musl, also alpine seems not to run tests.

pkgs/development/libraries/libffi/default.nix

@@ -1,9 +1,6 @@
 { stdenv, fetchurl, fetchpatch
 , autoreconfHook
 
-# libffi is used in darwin and linux with glibc stdenv
-# we cannot run checks within it
-, doCheck ? stdenv.hostPlatform.isMusl, dejagnu
 }:
 
 stdenv.mkDerivation rec {
@@ -28,10 +25,6 @@ stdenv.mkDerivation rec {
     NIX_HARDENING_ENABLE=''${NIX_HARDENING_ENABLE/fortify/}
   '';
 
-  checkInputs = [ dejagnu ];
-
-  inherit doCheck;
-
   dontStrip = stdenv.hostPlatform != stdenv.buildPlatform; # Don't run the native `strip' when cross-compiling.
 
   meta = with stdenv.lib; {