Enable the built-in FSMonitor as an experimental feature

If `feature.experimental` and `feature.manyFiles` are set, we now start
the built-in FSMonitor by default.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

repo-settings.c

@@ -2,12 +2,13 @@
 #include "config.h"
 #include "repository.h"
 #include "midx.h"
+#include "fsmonitor-ipc.h"
 
 #define UPDATE_DEFAULT_BOOL(s,v) do { if (s == -1) { s = v; } } while(0)
 
 void prepare_repo_settings(struct repository *r)
 {
-	int value;
+	int value, feature_many_files = 0;
 	char *strval;
 
 	if (r->settings.initialized)
@@ -62,6 +63,7 @@ void prepare_repo_settings(struct repository *r)
 		r->settings.use_builtin_fsmonitor = 1;
 
 	if (!repo_config_get_bool(r, "feature.manyfiles", &value) && value) {
+		feature_many_files = 1;
 		UPDATE_DEFAULT_BOOL(r->settings.index_version, 4);
 		UPDATE_DEFAULT_BOOL(r->settings.core_untracked_cache, UNTRACKED_CACHE_WRITE);
 	}
@@ -70,8 +72,12 @@ void prepare_repo_settings(struct repository *r)
 		r->settings.fetch_write_commit_graph = value;
 	UPDATE_DEFAULT_BOOL(r->settings.fetch_write_commit_graph, 0);
 
-	if (!repo_config_get_bool(r, "feature.experimental", &value) && value)
+	if (!repo_config_get_bool(r, "feature.experimental", &value) && value) {
 		UPDATE_DEFAULT_BOOL(r->settings.fetch_negotiation_algorithm, FETCH_NEGOTIATION_SKIPPING);
+		if (feature_many_files && fsmonitor_ipc__is_supported())
+			UPDATE_DEFAULT_BOOL(r->settings.use_builtin_fsmonitor,
+					    1);
+	}
 
 	/* Hack for test programs like test-dump-untracked-cache */
 	if (ignore_untracked_cache_config)