imagemagick, soxr, fftw, libraw: remove explicit gcc.lib

It is no longer needed after cc-wrapper fixes.

pkgs/applications/misc/audio/soxr/default.nix

@@ -17,9 +17,6 @@ stdenv.mkDerivation rec {
   '';
 
   nativeBuildInputs = [ cmake ];
-  buildInputs = [ (stdenv.cc.cc.lib or null) ];
-  # outputs TODO: gcc.lib might become a problem;
-  # here -out/lib/*.a got found and -lib/lib/*.so didn't
 
   meta = {
     description = "An audio resampling library";