SDL: add libiconv to fix build

pkgs/development/libraries/SDL/default.nix

@@ -1,4 +1,4 @@
-{ stdenv, fetchurl, fetchpatch, pkgconfig, audiofile, libcap
+{ stdenv, fetchurl, fetchpatch, pkgconfig, audiofile, libcap, libiconv
 , openglSupport ? false, mesa_noglu, mesa_glu
 , alsaSupport ? true, alsaLib
 , x11Support ? hostPlatform == buildPlatform, libXext, libICE, libXrandr
@@ -40,7 +40,8 @@ stdenv.mkDerivation rec {
   buildInputs = let
     notMingw = !hostPlatform.isMinGW;
   in optional notMingw audiofile
-  ++ optionals stdenv.isDarwin [ OpenGL CoreAudio CoreServices AudioUnit Kernel ];
+  ++ optionals stdenv.isDarwin [ OpenGL CoreAudio CoreServices AudioUnit Kernel ]
+  ++ [ libiconv ];
 
   # XXX: By default, SDL wants to dlopen() PulseAudio, in which case
   # we must arrange to add it to its RPATH; however, `patchelf' seems

pkgs/development/libraries/SDL2/default.nix

@@ -8,6 +8,7 @@
 , ibusSupport ? false, ibus
 , pulseaudioSupport ? true, libpulseaudio
 , AudioUnit, Cocoa, CoreAudio, CoreServices, ForceFeedback, OpenGL
+, libiconv
 }:
 
 # OSS is no longer supported, for it's much crappier than ALSA and
@@ -41,7 +42,8 @@ stdenv.mkDerivation rec {
   # Since `libpulse*.la' contain `-lgdbm', PulseAudio must be propagated.
   propagatedBuildInputs = lib.optionals x11Support [ libICE libXi libXScrnSaver libXcursor libXinerama libXext libXrandr libXxf86vm ] ++
     lib.optionals waylandSupport [ wayland wayland-protocols libxkbcommon ] ++
-    lib.optional pulseaudioSupport libpulseaudio;
+    lib.optional pulseaudioSupport libpulseaudio
+    ++ [ libiconv ];
 
   buildInputs = [ audiofile ] ++
     lib.optional openglSupport mesa_noglu ++