When I wanted to include this update in the FreeBSD port (emulators/wine-devel) which I maintain, I got the following on FreeBSD 11/i386:
../../tools/winegcc/winegcc -o ws2_32.dll.so --wine-objdir ../.. -fno-PIC -fasynchronous-unwind-tables -shared ws2_32.spec async.o socket.o version.res -liphlpapi -luser32 ../../libs/port/libwine_port.a -L/home/gerald/11-i386/lib -Wl,-delayload,iphlpapi.dll -Wl,-delayload,user32.dll -fstack-protector-strong -Wl,-rpath=/home/gerald/11-i386/lib/gcc9 -L/home/gerald/11-i386/lib/gcc9 ../xaudio2_7/xact_dll.c:84:5: error: unknown type name 'IXACT34Cue' 84 | IXACT34Cue IXACT34Cue_iface; | ^~~~~~~~~~
and
../xaudio2_7/xact_dll.c: At top level: ../xaudio2_7/xact_dll.c:293:50: error: unknown type name 'IXACT34Cue'; did you mean 'IXACT3Cue'? 293 | static inline XACT3CueImpl *impl_from_IXACT34Cue(IXACT34Cue *iface) | ^~~~~~~~~~ | IXACT3Cue
That looks like a general issue, not specific to this platform.
Looking at the source in question
typedef struct _XACT3CueImpl { IXACT3Cue IXACT3Cue_iface; #if XACT3_VER <= 0x0304 IXACT34Cue IXACT34Cue_iface; // <= Line 84 #endif
FACTCue *fact_cue; } XACT3CueImpl;
I am wondering whether this conditional compilation is the reason here (and why you may not have seen this)?
Gerald