Introduce our own shutdown callback mechanism.

Instead of adding stuff to `_shutdown()`, we can now register a shutdown
routine from the respective `init()` function of our modules.

This also has the advantage, that we're sure they're called in reverse
order from how the initialization happened.

I didn't simply use `atexit()` because POSIX says that the number of
possible callbacks is limited (min 32) and I was not sure whether
we will maybe extend this number at one point.

Signed-off-by: Steffen Jaeckel <s@jaeckel.eu>

src/command/cmd_defs.c

@@ -2840,6 +2840,14 @@ cmd_search_index_all(char* term)
     return results;
 }
 
+static void
+_cmd_uninit(void)
+{
+    cmd_ac_uninit();
+    g_hash_table_destroy(commands);
+    g_hash_table_destroy(search_index);
+}
+
 /*
  * Initialise command autocompleter and history
  */
@@ -2848,6 +2856,8 @@ cmd_init(void)
 {
     log_info("Initialising commands");
 
+    prof_add_shutdown_routine(_cmd_uninit);
+
     cmd_ac_init();
 
     search_index = g_hash_table_new_full(g_str_hash, g_str_equal, free, g_free);
@@ -2878,14 +2888,6 @@ cmd_init(void)
     prefs_free_aliases(aliases);
 }
 
-void
-cmd_uninit(void)
-{
-    cmd_ac_uninit();
-    g_hash_table_destroy(commands);
-    g_hash_table_destroy(search_index);
-}
-
 gboolean
 cmd_valid_tag(const char* const str)
 {

src/command/cmd_defs.h

@@ -42,7 +42,6 @@
 #include "ui/ui.h"
 
 void cmd_init(void);
-void cmd_uninit(void);
 
 Command* cmd_get(const char* const command);
 GList* cmd_get_ordered(const char* const tag);