* misc/ttyslot.c: Use ttyname_r instead of ttyname.
* assert/assert-perr.c: Use __strerror_r instead of strerror.
* assert/assert.c: De-ANSIdecl-fy. Update copyright.
* string/string.h: Declare __strerror_r.
* string/strerror_r.c: Make strerror_r a weak alias of __strerror_r.
* stdio-common/vfprintf.c: Save current errno value on entry so
that %m format finds the correct value.
* io/getwd.c: Use __strerror_r instead of strerror.
* misc/err.c (vwarn): Use %m printf format instead of explicitly
calling strerror.
* inet/rcmd.c: Likewise.
* misc/error.c (error, error_at_line): Use __strerror_r instead
of strerror when this function is available.
* stdlib/rand.c: Update copyright and de-ANSI-declfy.
* stdlib/random_r.c: Don't make srand_r weak alais of __srandom_r.
* stdlib/stdlib.h: Define prototype for rand_r.
* string/strfry.c: Update copyright. Use reentrant random functions.