x3daudio: fix lib exports
1. in case of x3daudio1_{0,1,2}, two exported functions are for some reason decorated (though only on 32bit) 2. tests show these functions should be stdcall, not cdecl; more exactly, header for 1.1 shows that too (1.7 header shows that changed at some point)
Signed-off-by: Rafał Mużyło galtgendo@o2.pl