Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

Regression tests for r197752 (handling of empty/NULL buffers).

Return -1 instead of 0 upon reaching EOF. This is somewhat ill-advised
because it means getdelim() returns -1 for both error and EOF, and
never returns 0. However, this is what the original GNU implementation
does, and POSIX inherited the bug.

Reported by: marcus@

Tests for getdelim().