haskellPackages.sbv: fix location of z3 executable

A lot of the functionality of the z3 library depends on it being able to
find the z3 executable on $PATH. Hard-coding it here means it will never
be unable to find it and z3 doesn't need to pollute $PATH.

pkgs/development/haskell-modules/configuration-nix.nix

@@ -511,4 +511,10 @@ self: super: builtins.intersectAttrs super {
   # Doctests hang only when compiling with nix.
   # https://github.com/cdepillabout/termonad/issues/15
   termonad = dontCheck super.termonad;
+
+  # Expects z3 to be on path so we replace it with a hard
+  sbv = overrideCabal super.sbv (drv: {
+    postPatch = ''
+      sed -i -e 's|"z3"|"${pkgs.z3}/bin/z3"|' Data/SBV/Provers/Z3.hs'';
+  });
 }