tree-wide: deduplicate network compat script

nix/networks/wpa_supplicant-compat.nix

@@ -0,0 +1,37 @@
+#
+# This loads the list of networks as a NixOS wpa_supplicant compatible attrset
+#
+let
+  sources = import ../../npins;
+  lib = import (sources.nixpkgs + "/lib");
+
+  # wpa_supplicant uses `strchr` to seek to the first `=`, so the only forbidden character is `=`.
+  escapePwdKey = lib.replaceStrings ["="] ["_"];
+
+  go = networkArgs @ {
+    ssid,
+    # Custom fields wrapping nixpkgs module options
+    hasPassword ? false,
+    scanOnLowSignal ? false,
+    randomizeMac ? false,
+    ...
+  }: {
+    ${ssid} = lib.mkMerge [
+      (builtins.removeAttrs networkArgs ["ssid" "hasPassword" "scanOnLowSignal" "randomizeMac"])
+      (lib.optionalAttrs hasPassword {
+        pskRaw = "ext:${escapePwdKey ssid}";
+      })
+      (lib.optionalAttrs scanOnLowSignal {
+        extraConfig = ''
+          bgscan="simple:30:-70:3600"
+        '';
+      })
+      (lib.optionalAttrs randomizeMac {
+        extraConfig = ''
+          mac_addr=1
+        '';
+      })
+    ];
+  };
+in
+  ns: lib.mkMerge (map go ns)