Fix errors when compiling on newer compilers (prototype definitions fix)

src/lock_vars.c

@@ -55,7 +55,7 @@ static bool set_locked_bool(bool* val, bool newval, pthread_mutex_t* mutex) {
     return newval;
 }
 
-bool get_spin() {
+bool get_spin(void) {
     return get_locked_bool(&spin, &spin_mutex);
 }
 
@@ -63,7 +63,7 @@ bool set_spin(bool newval) {
     return set_locked_bool(&spin, newval, &spin_mutex);
 }
 
-bool get_found_pongo() {
+bool get_found_pongo(void) {
    return get_locked_bool(&found_pongo, &found_pongo_mutex);
 }
 
@@ -71,7 +71,7 @@ bool set_found_pongo(bool val) {
     return set_locked_bool(&found_pongo, val, &found_pongo_mutex);
 }
 
-uint64_t get_ecid_wait_for_dfu() {
+uint64_t get_ecid_wait_for_dfu(void) {
     LOG(LOG_VERBOSE5, "locking ecid wait for dfu mutex for get");
     pthread_mutex_lock(&ecid_dfu_wait_mutex);
     uint64_t ret = ecid_wait_for_dfu;