data - user data to be passed to the specified callbacks
read_cb - a cb to replace fread(stdin)
writef_cb - a cb to repalce fprintf(stdout)
write_cb - a cb to replace fwrite(stdout)
getenv_cb - a cb to replace getenv
putenv_cb - a cb to replace putenv
iterenv_cb - a cb to replace the default environment iteration
function (which just wraps walking the envp array)
DESCRIPTION
cgiwrap_init_emu sets up the cgiwrap subsystem for use
in an emulated environment where you are providing
routines to use in place of the standard routines, ie
when used to interface with a server or scripting
language.
See cgi/cgiwrap.h for the exact definitions of the
callback functions.