Add pw_in_valgrind() to check running in valgrind

In valgrind we don't want to unload the plugins because then valgrind
doesn't know the symbol names where things leaked.
Parse the VALGRIND env variable and use this to avoid calling
dlclose for a better valgrind experience.

src/pipewire/impl-module.c

@@ -322,7 +322,7 @@ void pw_impl_module_destroy(struct pw_impl_module *module)
 
 	pw_properties_free(module->properties);
 
-	if (dlclose(impl->hnd) != 0)
+	if (!pw_in_valgrind() && dlclose(impl->hnd) != 0)
 		pw_log_warn(NAME" %p: dlclose failed: %s", module, dlerror());
 	free(impl);
 }

src/pipewire/pipewire.c

@@ -74,6 +74,7 @@ struct support {
 	struct registry *registry;
 	struct spa_support support[MAX_SUPPORT];
 	uint32_t n_support;
+	unsigned int in_valgrind:1;
 };
 
 static struct registry global_registry;
@@ -154,6 +155,7 @@ unref_plugin(struct plugin *plugin)
 	if (--plugin->ref == 0) {
 		spa_list_remove(&plugin->link);
 		pw_log_debug("unloaded plugin:'%s'", plugin->filename);
+		if (!global_support.in_valgrind)
 			dlclose(plugin->hnd);
 		free(plugin->filename);
 		free(plugin);
@@ -367,6 +369,9 @@ void pw_init(int *argc, char **argv[])
 	if (support->registry != NULL)
 		return;
 
+	if ((str = getenv("VALGRIND")))
+		support->in_valgrind = pw_properties_parse_bool(str);
+
 	if ((str = getenv("PIPEWIRE_DEBUG")))
 		configure_debug(support, str);
 
@@ -506,6 +511,12 @@ const char *pw_get_host_name(void)
 	return hname;
 }
 
+SPA_EXPORT
+bool pw_in_valgrind(void)
+{
+	return global_support.in_valgrind;
+}
+
 /** Get the client name
  *
  * Make a new PipeWire client name that can be used to construct a remote.

src/pipewire/pipewire.h

@@ -136,6 +136,8 @@ pw_get_host_name(void);
 const char *
 pw_get_client_name(void);
 
+bool pw_in_valgrind(void);
+
 enum pw_direction
 pw_direction_reverse(enum pw_direction direction);