CMake: enable C (Homebrew LLVM's config needs it); Kate: highlighting, language server setup, install script

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

editors/kate/install.sh

@@ -0,0 +1,27 @@
+#!/usr/bin/env bash
+# Installs Finch support for Kate (also KWrite and KDevelop):
+#   - syntax highlighting:  ~/.local/share/org.kde.syntax-highlighting/syntax/finch.xml
+#   - the language server:  adds "finch" to ~/.config/kate/lspclient/settings.json
+# Then restart Kate and enable Settings → Configure Kate → Plugins → "LSP Client".
+set -eu
+here="$(cd "$(dirname "$0")" && pwd)"
+data="${XDG_DATA_HOME:-$HOME/.local/share}/org.kde.syntax-highlighting/syntax"
+conf="${XDG_CONFIG_HOME:-$HOME/.config}/kate/lspclient"
+mkdir -p "$data" "$conf"
+cp "$here/finch.xml" "$data/finch.xml"
+echo "highlighting: $data/finch.xml"
+
+# merge into the user's LSP settings instead of replacing them
+python3 - "$conf/settings.json" "$here/lspclient.json" <<'PY'
+import json, os, sys
+path, ours = sys.argv[1], json.load(open(sys.argv[2]))
+cur = {}
+if os.path.exists(path) and os.path.getsize(path) > 0:
+    cur = json.load(open(path))
+cur.setdefault("servers", {}).update(ours["servers"])
+with open(path, "w") as f:
+    json.dump(cur, f, indent=4)
+    f.write("\n")
+print("language server: " + path)
+PY
+command -v finch > /dev/null || echo "note: 'finch' isn't on your PATH yet; Kate starts the language server with 'finch lsp'"