Remove structVersion field from PaHostApiInfo, PaDeviceInfo and PaStreamInfo

[PortAudio-admin]

Issue created by @RossBencina

PaHostApiInfo, PaDeviceInfo and PaStreamInfo structures have a structVersion field. Other structures don't. It has been proposed (and generally agreed) that we should remove these fields because the versioning capabilities they provide are not easily usable.

Instead, a global library versioning mechanism will be provided (documented in ticket: #173)

We discussed whether breaking binary compatibility was a good idea. Bjorn started here:
http://music.columbia.edu/pipermail/portaudio/2008-February/008318.html

Richard Ash suggested that it wasn't a big deal to break compatibility since we can bump package version numbers.
http://music.columbia.edu/pipermail/portaudio/2008-February/008324.html
In the same basis Richard also provides the analysis to support removing the struct version numbers. He concludes:

On this basis I would suggest that structure version numbering is just
not worth it - almost no application developer is going to jump through
the kind of complexity you describe to support multiple library versions
at runtime.

Since this change breaks binary structure compatibility and should be performed in conjunction with the following tickets that also alter struct layout

• Portaudio should expose host API specific stream information #169 Portaudio should expose host API specific stream information
• API calling convention and pack #58 API calling convention and pack

[PortAudio-admin]

Comment by @RossBencina

FYI this is all uses of structVersion as of r1666:

C:\amtrunk_wd\external-libs\portaudio>grep -d -n structVersion *.c *.cpp *.h
File src\common\pa_front.c:
575             PA_LOGAPI(("\t\tint structVersion: %d\n", info->structVersion ));
717             PA_LOGAPI(("\t\tint structVersion: %d\n", result->structVersion));
1508            PA_LOGAPI(("\t\tint structVersion: %d\n", result->structVersion));
File src\hostapi\alsa\pa_linux_alsa.c:
736         (*hostApi)->info.structVersion = 1;
931         deviceInfo->structVersion = -1;
1119        baseDeviceInfo->structVersion = 2;
File src\hostapi\asihpi\pa_linux_asihpi.c:
648                     baseDeviceInfo->structVersion = 2;
691                     baseDeviceInfo->structVersion = 2;
773         baseApiInfo->structVersion = 1;
1821        stream->baseStreamRep.streamInfo.structVersion = 1;
File src\hostapi\coreaudio\pa_mac_core.c:
491         deviceInfo->structVersion = 2;
581         (*hostApi)->info.structVersion = 1;
File src\hostapi\coreaudio\pa_mac_core_old.c:
289         deviceInfo->structVersion = 2;
880         (*hostApi)->info.structVersion = 1;
File src\hostapi\dsound\pa_win_ds.c:
1057        (*hostApi)->info.structVersion = 1;
1125                deviceInfo->structVersion = 2;
File src\hostapi\jack\pa_jack.c:
572             curDevInfo->structVersion = 2;
743         (*hostApi)->info.structVersion = 1;
File src\hostapi\oss\pa_unix_oss.c:
253         (*hostApi)->info.structVersion = 1;
298         deviceInfo->structVersion = 2;
File src\hostapi\skeleton\pa_hostapi_skeleton.c:
148         (*hostApi)->info.structVersion = 1;
181                 deviceInfo->structVersion = 2;
File src\hostapi\wasapi\pa_win_wasapi.c:
1095        (*hostApi)->info.structVersion               = 1;
1198                deviceInfo->structVersion = 2;
File src\hostapi\wdmks\pa_win_wdmks.c:
1808        (*hostApi)->info.structVersion = 1;
1841                deviceInfo->structVersion = 2;
File src\hostapi\wmme\pa_win_wmme.c:
929         (*hostApi)->info.structVersion = 1;
1004                    deviceInfo->structVersion = 2;
1047                    deviceInfo->structVersion = 2;
File src\hostapi\asio\pa_asio.cpp:
1088        (*hostApi)->info.structVersion = 1;
1179                    deviceInfo->structVersion = 2;
File src\hostapi\asio\pa_asio.new_set_sample_rate.cpp:
1119        (*hostApi)->info.structVersion = 1;
1211                    deviceInfo->structVersion = 2;
File include\portaudio.h:
248         int structVersion;
451         int structVersion;  /* this is struct version 2 */
966         int structVersion;

[PortAudio-admin]

Comment by @RossBencina

TRAC migration: propagating ticket status from TRAC