octavePackages.gsl: Propagate libgsl to octave.withPackages environment (#496585)

pkgs/development/octave-modules/gsl/default.nix

@@ -1,5 +1,6 @@
 {
   buildOctavePackage,
+  stdenv,
   lib,
   fetchurl,
   gsl,
@@ -14,7 +15,7 @@ buildOctavePackage rec {
     sha256 = "1lvfxbqmw8h1nlrxmvrl6j4xffmbzxfhdpxz3vrc6lg2g4jwaa6h";
   };
 
-  buildInputs = [
+  propagatedBuildInputs = [
     gsl
   ];
 
@@ -23,8 +24,9 @@ buildOctavePackage rec {
     license = lib.licenses.gpl2Plus;
     maintainers = with lib.maintainers; [ KarlJoad ];
     description = "Octave bindings to the GNU Scientific Library";
-    # When used in an `octave.withPackages` environment, octave fails to find
-    # libgsl.so from some reason.
-    broken = true;
+    # gsl_sf.cc:1782:11: error: no member named 'is_real_type' in 'octave_value'
+    #  1782 |     if (! ISREAL(args(i)))
+    #       |           ^~~~~~~~~~~~~~~
+    broken = stdenv.hostPlatform.isDarwin;
   };
 }