Procedure to compile a system patch

[Ernie Luzar]

Hello list;

I have a patch file for contrib/ipfilter/tools/ippool.c

I have never compiled the base system source so have no idea about how
to do this. I only want to compile the things necessary to apply this
patch, not the whole system or even the just the kernel.

I used this svn command to download just the necessary source

svnlite co svn://svn.freebsd.org/base/releng/11.0/contrib/ipfilter/tools 
/usr/src/contrib/ipfilter/tools

Then I patched ippool.c

Now I am stuck. What command do I enter to compile ippool.c to get an 
updated /sbin/ippool executable module?