Fixed no trace compile
Merged revision(s) 29888-29926 from ptlib/branches/v2_12:
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r29926
Make sure trace level is reset to default (zero) on shutdown so when re-initialised it does not get spurious logs. 
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r29919
Fixed Mac OS-X build
More portability tweaks.
Fixed losing all the trace option bits in PTrace::Initialise()
Portability fix, weirdly, iPhoneOS has unsigned long long but not long long.
Merged revision(s) 29927-29945 from ptlib/branches/v2_12:
Changed test for QWAVE (QoS) support in Windows. In Windows Server 2008 R2 it is an optional component so may or may not be installed. Juts checking OS version not sufficient. Now we check for if we can load QWAVE.DLL before trying it.