Convert emacs-vterm and isync-oauth2 to overlays

overlays/emacs-vterm.nix

@@ -0,0 +1,12 @@
+{ config, lib, pkgs, ... }:
+
+with pkgs;
+
+{
+  nixpkgs.overlays = [
+    (final: prev: {
+      emacs-vterm = ((emacsPackagesFor emacs28NativeComp).emacsWithPackages
+        (epkgs: with epkgs; [ vterm pdf-tools ]));
+    })
+  ];
+}

overlays/isync-oauth2.nix

@@ -0,0 +1,14 @@
+{ config, lib, pkgs, ... }:
+
+with pkgs;
+
+{
+
+  nixpkgs.overlays = [
+    (final: prev: {
+      isync-oauth2 = isync.overrideAttrs (div: rec {
+        buildInputs = [ openssl db patched-cyrus-sasl-oauth2 zlib ];
+      });
+    })
+  ];
+}