more errno.h removal

apps/app_directory.c

apps/app_externalivr.c

apps/app_meetme.c

apps/app_milliwatt.c

apps/app_system.c

apps/app_zapbarge.c

pbx/pbx_ael.c

pbx/pbx_config.c

pbx/pbx_dundi.c

pbx/pbx_loopback.c

pbx/pbx_lua.c

pbx/pbx_realtime.c

pbx/pbx_spool.c