GCC compile fixes

Also there were some funky undefined behavior warnings:
/home/i30817/Documents/Netbeans_projects/blah/mt32emu/src/Synth.cpp: In member function ‘void MT32Emu::Synth::produceLA32Output(MT32Emu::Sample*, MT32Emu::Bit32u)’:
/home/i30817/Documents/Netbeans_projects/blah/mt32emu/src/Synth.cpp:1487:94: warning: operation on ‘buffer’ may be undefined [-Wsequence-point]
/home/i30817/Documents/Netbeans_projects/blah/mt32emu/src/Synth.cpp:1487:94: warning: operation on ‘buffer’ may be undefined [-Wsequence-point]
/home/i30817/Documents/Netbeans_projects/blah/mt32emu/src/Synth.cpp:1487:94: warning: operation on ‘buffer’ may be undefined [-Wsequence-point]
/home/i30817/Documents/Netbeans_projects/blah/mt32emu/src/Synth.cpp:1492:51: warning: operation on ‘buffer’ may be undefined [-Wsequence-point]
/home/i30817/Documents/Netbeans_projects/blah/mt32emu/src/Synth.cpp: In member function ‘void MT32Emu::Synth::convertSamplesToOutput(MT32Emu::Sample*, MT32Emu::Bit32u, bool)’:
/home/i30817/Documents/Netbeans_projects/blah/mt32emu/src/Synth.cpp:1519:58: warning: operation on ‘buffer’ may be undefined [-Wsequence-point]

Which i don't feel competent to do anything about.