I'm interested in seeing Ridley Combs' dcrt1 patch merged.  Here's an
updated version of the most recently posted patch[1], taken from [2]
with [3] squashed in and a minor modification to remove the gotos from
the _ERROR macro.  The only differences between [1] and [2] are fixing
a few warnings and removing an extra space.

[1] https://www.openwall.com/lists/musl/2020/03/29/9
[2] https://github.com/rcombs/musl/commit/740155e21f7057a33e75a9ed4cb6fbf07f75d2a7
[3] https://github.com/rcombs/musl/commit/8ff8f3422510302c0ea47af7de9d59777069ed72