If FIRST is non-zero, sets global variables HZ, HIST_DIMENSION,
HIST_DIMENSION_ABBREV, HIST_SCALE. If FIRST is zero, checks
that the new histogram is compatible with already-set values
of those variables and emits an error if that's not so. */
static void
If FIRST is non-zero, sets global variables HZ, HIST_DIMENSION,
HIST_DIMENSION_ABBREV, HIST_SCALE. If FIRST is zero, checks
that the new histogram is compatible with already-set values
of those variables and emits an error if that's not so. */
static void