port: more UB/bug fixes

src/lib/mema.c

@@ -219,6 +219,7 @@ void memaReset(void *heapaddr, u32 heapsize)
 {
 	struct memaspace *space;
 
+#ifdef PLATFORM_N64
 #ifndef DEBUG
 	// Adding an amount to the heap size here means that mema can allocate past
 	// the end of its heap. This would overflow into the gun names language
@@ -226,6 +227,7 @@ void memaReset(void *heapaddr, u32 heapsize)
 	// meant for it to be ifdef instead?
 	// @bug @dangerous
 	heapsize += 0x8e0;
+#endif
 #endif
 
 	g_MemaHeap.unk000 = 0;

src/lib/naudio/n_csplayer.c

@@ -936,12 +936,18 @@ void __n_CSPHandleMIDIMsg(N_ALCSPlayer *seqp, N_ALEvent *event)
 						} else if (vs->phase == AL_PHASE_SUSTREL) {
 							vs->phase = AL_PHASE_RELEASE;
 
+#ifdef AVOID_UB
+							chanstate = &seqp->chanState[chan];
+#endif
 							// @bug: chanstate is uninitialised
 							if (chanstate->unk24) {
 								__n_seqpReleaseVoice((N_ALSeqPlayer*)seqp,
 										&vs->voice,
 										(seqp->chanState[chan].releaseTime < AL_USEC_PER_FRAME ? AL_USEC_PER_FRAME : seqp->chanState[chan].releaseTime));
 							} else {
+#ifdef AVOID_UB
+								vstate = __n_lookupVoice((N_ALSeqPlayer*)seqp, key, chan);
+#endif
 								__n_seqpReleaseVoice((N_ALSeqPlayer*)seqp,
 										&vs->voice,
 										vstate->sound->envelope->releaseTime < AL_USEC_PER_FRAME ? AL_USEC_PER_FRAME : vstate->sound->envelope->releaseTime);