Small fix for game load crashes on Windows

[IcyChills]

A fix for crash caused when loading save games on Windows under Doom 3. Found in snd_emitter.cpp. The issue is also in the fhDoom source. Just wanted to share, feel free to close the issue.

/*
===================
idSoundChannel::GatherChannelSamples

Will always return 44kHz samples for the given range, even if it deeply looped or
out of the range of the unlooped samples. Handles looping between multiple different
samples and leadins
===================
*/
void idSoundChannel::GatherChannelSamples(int sampleOffset44k, int sampleCount44k, float *dest) const {
	float *dest_p = dest;
	int len;

	// Check for null decoder
	if (!decoder) {
		// Fill destination with zeroes if decoder is null
		memset(dest_p, 0, sampleCount44k * sizeof(dest_p[0]));
		return;
	}

	// Negative offset times will zero-fill
	if (sampleOffset44k < 0) {
		len = -sampleOffset44k;
		if (len > sampleCount44k) {
			len = sampleCount44k;
		}
		memset(dest_p, 0, len * sizeof(dest_p[0]));
		dest_p += len;
		sampleCount44k -= len;
		sampleOffset44k += len;
	}

	// Handle lead-in sample
	idSoundSample *leadin = leadinSample;
	if (!leadin || sampleOffset44k < 0 || sampleCount44k <= 0) {
		memset(dest_p, 0, sampleCount44k * sizeof(dest_p[0]));
		return;
	}

	if (sampleOffset44k < leadin->LengthIn44kHzSamples()) {
		len = leadin->LengthIn44kHzSamples() - sampleOffset44k;
		if (len > sampleCount44k) {
			len = sampleCount44k;
		}

		// Decode the sample if decoder is valid
		decoder->Decode(leadin, sampleOffset44k, len, dest_p);
		dest_p += len;
		sampleCount44k -= len;
		sampleOffset44k += len;
	}

	// Zero-fill if not looping
	if (!soundShader || !(parms.soundShaderFlags & SSF_LOOPING)) {
		memset(dest_p, 0, sampleCount44k * sizeof(dest_p[0]));
		return;
	}

	// Looping sample handling
	idSoundSample *loop = soundShader->entries[0];
	if (!loop) {
		memset(dest_p, 0, sampleCount44k * sizeof(dest_p[0]));
		return;
	}

	sampleOffset44k -= leadin->LengthIn44kHzSamples();

	while (sampleCount44k > 0) {
		int totalLen = loop->LengthIn44kHzSamples();
		sampleOffset44k %= totalLen;

		len = totalLen - sampleOffset44k;
		if (len > sampleCount44k) {
			len = sampleCount44k;
		}

		// Decode the loop sample
		decoder->Decode(loop, sampleOffset44k, len, dest_p);

		dest_p += len;
		sampleCount44k -= len;
		sampleOffset44k += len;
	}
}