qt: Add logging category
* qt/pinentry_debug.cpp, qt/pinentry_debug.h: New. * qt/Makefile.am (pinentry_qt_SOURCES): Add new files. * qt/main.cpp (main): Use logging category for debug messages.
The logging category allows enabling or disabling logging of messages
of certain types. By default, only warnings and more severe messages
are enabled.
- GnuPG-bug-id: T3659