Use glib for allocations in all plugins

Continuation of 83032b1aa

plugins/fishlim/keystore.h

@@ -28,11 +28,11 @@
 #include <stdbool.h>
 #include <stddef.h>
 
+#include <glib.h>
+
 char *keystore_get_key(const char *nick);
 bool keystore_store_key(const char *nick, const char *key);
 bool keystore_delete_nick(const char *nick);
 
-void keystore_secure_free(void *ptr, size_t size);
-
 #endif