This is one of those patches which will either make matters far
simpler after the bugs shake out, or will get reverted pretty quick
once we realize that it is a stupid idea.
We now post-process the config.h file into a new event-config.h file,
whose macros are prefixed with _EVENT_ and which is thus safe for
headers to include. Using this, we can define replacement timeval
manipulation functions in evutil.h, and use them uniformly through our
code. We can also detect which headers are needful in event.h, and
include them as required.
This is also the perfect time to remove the long-deprecated acconfig.h
file, so that autoheader no longer warns.
Should resolve the following issues:
[ 1826530 ] Header files should have access to autoconf output.
[ 1826545 ] acconfig.h is deprecated.
[ 1826564 ] On some platforms, event.h can't be included alone.
svn:r492
