Update to the latest PortAudio (PA) and fix PA issues on MacOS X Snow Leopard (thanks Saul Ibarra Corretge for the fix)

[nanang]

Some errors have been reported on building/running PJSIP on MacOS X Snow Leopard:

src/../../../portaudio/src/hostapi/coreaudio/pa_mac_core.c:510: warning: 'AudioDeviceGetProperty' is deprecated (declared at /System/Library/Frameworks/CoreAudio.framework/Headers/AudioHardware.h:2367)
src/../../../portaudio/src/hostapi/coreaudio/pa_mac_core.c: In function 'OpenAndSetupOneAudioUnit':
src/../../../portaudio/src/hostapi/coreaudio/pa_mac_core.c:800: error: 'ComponentDescription' undeclared (first use in this function)
src/../../../portaudio/src/hostapi/coreaudio/pa_mac_core.c:800: error: (Each undeclared identifier is reported only once
src/../../../portaudio/src/hostapi/coreaudio/pa_mac_core.c:800: error: for each function it appears in.)
src/../../../portaudio/src/hostapi/coreaudio/pa_mac_core.c:800: error: expected ';' before 'desc'
src/../../../portaudio/src/hostapi/coreaudio/pa_mac_core.c:801: error: 'Component' undeclared (first use in this function)
src/../../../portaudio/src/hostapi/coreaudio/pa_mac_core.c:801: error: expected ';' before 'comp'
src/../../../portaudio/src/hostapi/coreaudio/pa_mac_core.c:866: error: 'desc' undeclared (first use in this function)
src/../../../portaudio/src/hostapi/coreaudio/pa_mac_core.c:872: error: 'comp' undeclared (first use in this function)

Solution provided by Saul Ibarra Corretge can be found ​here.