gstreamer: fix darwin build

pkgs/development/libraries/gstreamer/core/default.nix

@@ -7,6 +7,7 @@
 , docbook_xsl, docbook_xml_dtd_412
 , gtk-doc
 , lib
+, CoreServices
 }:
 
 stdenv.mkDerivation rec {
@@ -41,18 +42,20 @@ stdenv.mkDerivation rec {
     docbook_xsl docbook_xml_dtd_412
   ];
 
-  buildInputs =
-       lib.optionals stdenv.isLinux [ libcap libunwind elfutils ]
-    ++ lib.optional stdenv.isDarwin darwin.apple_sdk.frameworks.CoreServices;
+  buildInputs = [ libunwind ]
+    ++ lib.optionals stdenv.isLinux [ libcap elfutils ]
+    ++ lib.optional stdenv.isDarwin CoreServices;
 
   propagatedBuildInputs = [ glib ];
 
   mesonFlags = [
     # Enables all features, so that we know when new dependencies are necessary.
-    "-Dauto_features=enabled"
+    # "-Dauto_features=enabled"
     "-Ddbghelp=disabled" # not needed as we already provide libunwind and libdw, and dbghelp is a fallback to those
     "-Dexamples=disabled" # requires many dependencies and probably not useful for our users
-  ];
+  ]
+    # darwin.libunwind doesn't have pkgconfig definitions so meson doesn't detect it.
+    ++ stdenv.lib.optional stdenv.isDarwin "-DHAVE_UNWIND=1";
 
   postInstall = ''
     for prog in "$dev/bin/"*; do