Split out a new libnixflake

Co-authored-by: Robert Hensing <roberth@users.noreply.github.com>

src/libflake/flake-settings.hh

@@ -0,0 +1,39 @@
+#pragma once
+///@file
+
+#include "types.hh"
+#include "config.hh"
+#include "util.hh"
+
+#include <map>
+#include <limits>
+
+#include <sys/types.h>
+
+namespace nix {
+
+struct FlakeSettings : public Config
+{
+    FlakeSettings();
+
+    Setting<bool> useRegistries{this, true, "use-registries",
+        "Whether to use flake registries to resolve flake references.",
+        {}, true, Xp::Flakes};
+
+    Setting<bool> acceptFlakeConfig{this, false, "accept-flake-config",
+        "Whether to accept nix configuration from a flake without prompting.",
+        {}, true, Xp::Flakes};
+
+    Setting<std::string> commitLockFileSummary{
+        this, "", "commit-lockfile-summary",
+        R"(
+          The commit summary to use when committing changed flake lock files. If
+          empty, the summary is generated based on the action performed.
+        )",
+        {}, true, Xp::Flakes};
+};
+
+// TODO: don't use a global variable.
+extern FlakeSettings flakeSettings;
+
+}