make CTRL+Z work in the REPL

Editline just wasn't being built with --enable-sigstop lol

Change-Id: I35a78f74ea100d97f26b2b41990deb373fd9cd9a

doc/manual/rl-next/repl-tstp.md

@@ -0,0 +1,7 @@
+---
+synopsis: "REPL now supports CTRL+Z to suspend"
+credits: [Qyriad]
+category: Improvements
+---
+
+Editline is now built with SIGTSTP support, so now typing CTRL+Z in the REPL will suspend the REPL and allow it to be resumed later or backgrounded.

package.nix

@@ -18,6 +18,7 @@
   cmake,
   curl,
   doxygen,
+  editline-lix ? __forDefaults.editline-lix,
   editline,
   flex,
   git,
@@ -73,6 +74,10 @@
       ];
     };
 
+    editline-lix = editline.overrideAttrs (prev: {
+      configureFlags = prev.configureFlags or [ ] ++ [ (lib.enableFeature true "sigstop") ];
+    });
+
     lix-doc = pkgs.callPackage ./lix-doc/package.nix { };
     build-release-notes = pkgs.callPackage ./maintainers/build-release-notes.nix { };
   },
@@ -236,7 +241,7 @@ stdenv.mkDerivation (finalAttrs: {
       bzip2
       xz
       brotli
-      editline
+      editline-lix
       openssl
       sqlite
       libarchive
@@ -376,7 +381,7 @@ stdenv.mkDerivation (finalAttrs: {
   # Export the patched version of boehmgc.
   # flake.nix exports that into its overlay.
   passthru = {
-    inherit (__forDefaults) boehmgc-nix build-release-notes;
+    inherit (__forDefaults) boehmgc-nix editline-lix build-release-notes;
 
     # The collection of dependency logic for this derivation is complicated enough that
     # it's easier to parameterize the devShell off an already called package.nix.