This is the printf implementation from FreeBSD.  It was imported on 2019-05-12,
from SVN revision 347514 (but the code hadn't been touched for 2 years before
that.)

Please don't reindent or otherwise mangle the files to make importing fixes
easy (not that there are significant changes likely to happen...)

The changes to this code are published under FreeBSD's license as listed in the
file headers.  If you change license, please make that as obvious as possible.