www/node: Fix build on FreeBSD 9.x

Patch log-utils.h in the in-tree v8 source code, allowing it to compile
using G++ 4.8 on FreeBSD 9.x. The code unfortunately relies on compiler
intrinsics instead of including the necessary standard headers for
handling C-style I/O and variadic arguments in its internal logging
functions.

This commit log and the code changes were provided by:

Brendan Molloy (fmtq via IRC) - Thank you!

PR: 205401
Reported by: JSG (via freenode IRC)
Approved by: blanket (portmgr)