Instead of arbitrarily breaking the output at 65536 bytes, we'll do our split: switch to getline() for line/pattern matching
best to fit larger buffer sizes until we run out of memory. We'll
Get rid of split's home-grown logic for growing the buffer; arbitrarily
double the buffer size until we hit MAXBSIZE, at which point we'll only breaking at LONG_MAX bytes instead of 65536 bytes gives us much more
increase by MAXBSIZE bytes.
Sponsored by: wiggle room. Additionally, we'll actually fail out entirely if we can't
fit a line, which makes noticing this class of problem much easier.
Sponsored by: Klara, Inc.
Differential Revision: https://reviews.freebsd.org/D36323