basicfuncs: Use gint64 instead of glong

Since parse_number was modified earlier to always use gint64, on 32 bit
platforms, basicfuncs that used parse_number() were broken, because they
were not migrated to gint64 yet. This patch fixes that, by converting
all relevant glongs to gint64.

Reported-by: Peter Czanik <czanik@balabit.hu>
Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>