GCC 16 on Arch Linux no longer implicitly includes certain standard
headers. This causes 'not declared' errors for POSIX functions.
- PiPedalCommon/src/CMakeLists.txt: Link asound library for ALSA sequencer
- DBusDispatcher.cpp: Add <unistd.h> for read()/write()/close()
- AuxInTest.cpp: Add <unistd.h> for sleep()
- kconfigMain.cpp: Add <unistd.h> for getuid()
- ModFileTypes.cpp: Add <mutex> for std::mutex/std::lock_guard