sunos: preemptively fix uv_exepath(size=1)
sunos: preemptively fix uv_exepath(size=1)

I'm not 100% sure whether the behavior of readlink() with size=0 is
well-defined on Solaris; it can return either 0 or fail with EINVAL.
POSIX is not explicit about the mandated behavior.

This commit adds a little caution and makes it skip the readlink()
call when size=1 and simply writes the terminating zero byte.

PR-URL: https://github.com/libuv/libuv/pull/104
Reviewed-By: Saúl Ibarra Corretgé <8a7991f6950ea189abf159d6ec98d2fcc13dc5f6@gmail.com>

unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso