these functions.

The [v]asprintf() functions are convenient shorthand, but suffer from
a number of problems, portability, cornercases and performance being
the most relevant to Varnish. 

Static buffers on the stack (see [v]bprintf macros, or sbufs (vsb)
are always better choices for us.



git-svn-id: http://www.varnish-cache.org/svn/trunk/varnish-cache@4581 d4fa192b-c00b-0410-8231-f00ffab90ce4