events: fix SDL_PeepEvents() returning 0 on error

Signed-off-by: Amelia Clarke <selene@perilune.dev>
diff --git a/src/events/SDL_events.c b/src/events/SDL_events.c
index aeb2283..7551e4a 100644
--- a/src/events/SDL_events.c
+++ b/src/events/SDL_events.c
@@ -1167,7 +1167,8 @@
         if (action == SDL_ADDEVENT) {
             CHECK_PARAM(!events) {
                 SDL_UnlockMutex(SDL_EventQ.lock);
-                return SDL_InvalidParamError("events");
+                SDL_InvalidParamError("events");
+                return -1;
             }
             for (i = 0; i < numevents; ++i) {
                 used += SDL_AddEvent(&events[i]);