in pathconf, -1, not 0, means unsupported.. syncio presumably works, too.
[musl] / src / math / __fpclassifyl.c
2011-06-30 Rich Felkerfix error in previous ld80 fpclassify commit
2011-06-30 Rich Felkercatch invalid ld80 bit patterns and treat them as nan
2011-02-12 Rich Felkerinitial check-in, version 0.5.0