* modules/snprintf (Depends-on): Remove minmax.

* modules/snprintf (Depends-on): Remove minmax.
(Maintainer): Add self.
* lib/.cppi-disable: Add snprintf.h, socket_.h.
* lib/snprintf.c: Include <errno.h> and <limits.h>.
(EOVERFLOW): Define if the system does not.
Do not include "minmax.h"; it wasn't used.
(snprintf): Don't assume size_t promotes to an unsigned type.
Fix bug when generated string was too long for the buffer: the
buffer's contents are supposed to be the initial prefix of the
output.  Don't assume vasnprintf returns EOVERFLOW if the size
exceeds INT_MAX; do the check ourselves.