pkgsMusl.libiscsi: fix build

pkgs/development/libraries/libiscsi/default.nix

@@ -13,8 +13,13 @@ stdenv.mkDerivation rec {
 
   nativeBuildInputs = [ autoreconfHook ];
 
+  # This can be removed after >=1.20.0, or if the build suceeds with
+  # pie enabled (default on Musl).
+  hardeningDisable = [ "pie" ];
+
   # This problem is gone on libiscsi master.
-  NIX_CFLAGS_COMPILE = if stdenv.hostPlatform.is32bit then "-Wno-error=sign-compare" else null;
+  NIX_CFLAGS_COMPILE =
+    lib.optional stdenv.hostPlatform.is32bit "-Wno-error=sign-compare";
 
   meta = with lib; {
     description = "iscsi client library and utilities";