Various: Fix some compile warnings; from Gianfranco

api/graphics2_unix.cpp

client/app_control.cpp

client/app_start.cpp

client/cs_platforms.cpp

client/gpu_detect.cpp

client/hostinfo_unix.cpp

client/log_flags.cpp

client/switcher.cpp

lib/crypt.cpp

lib/diagnostics.cpp

lib/procinfo_unix.cpp