[GinjaNinja32]

See discord conversation.

tl;dr size_t(infinity) == 0 but int(infinity) == -2^31, causing an out-of-bounds access. This PR results in an infinitely-playing sound, but that's better than a crash.

TODO: prevent infinite pitch somewhere earlier than this.

[GinjaNinja32]

With master plus some debug prints, running
EmptyEpsilon server_scenario=scenario_27_liberation.lua scenario_settings='First=Seconds;Second=Seconds;Third=Seconds',
selecting main screen, then unpausing, I get:

INFO: onMixSamples(count=4096, sound->samples=438440, sound->samplerate=44100, sound->channels=2, index=115680.98, pitch=0.70, index_offset=0.70)
INFO: onMixSamples(count=4096, sound->samples=438440, sound->samplerate=44100, sound->channels=2, index=117120.98, pitch=0.70, index_offset=0.70)
INFO: onMixSamples(count=4096, sound->samples=438440, sound->samplerate=44100, sound->channels=2, index=118560.98, pitch=0.70, index_offset=0.70)
INFO: Loaded: sfx/laser_fire.wav of 0.90 seconds
INFO: onMixSamples(count=4096, sound->samples=39651, sound->samplerate=44100, sound->channels=1, index=0.00, pitch=inf, index_offset=inf)
INFO: idx=inf size_t(idx)=0 int(idx)=-2147483648 sss=39651
/usr/include/c++/16/bits/stl_vector.h:1272: std::vector<_Tp, _Alloc>::const_reference std::vector<_Tp, _Alloc>::operator[](size_type) const [with _Tp = short int; _Alloc = std::allocator<short int>; const_reference = const short int&; size_type = long unsigned int]: Assertion '__n < this->size()' failed.

[daid]

preventing crashes is always good.