_POSIX_C_SOURCE    21 src/dps8/dps8_duma.h #  define _POSIX_C_SOURCE 1
_POSIX_C_SOURCE    49 src/simh/linehistory.c # define _POSIX_C_SOURCE 200809L
_POSIX_C_SOURCE    49 src/simh/linehistory.h # define _POSIX_C_SOURCE 200809L