Applying local patches after updating FreeBSD source

[Maxim Khitrov]

Hi all,

When I need to apply a custom patch to a port, I can set EXTRA_PATCHES
make variable in /usr/local/etc/ports.conf (when using portconf), and
the patch will be automatically applied whenever that port is built.
Is there equivalent functionality for building FreeBSD world and
kernel?

When I run 'make update' in /usr/src, csup overwrites all local
changes. There is a LOCAL_PATCHES variable, but it seems to apply only
to 'make release'.

If possible, I would like to avoid writing custom scripts for updating
and building world, because at some point I will forget to use the
script and build everything without the patches. How can I preserve
the current behavior of running 'make update && make buildworld
buildkernel' while automatically applying custom patches in between?

- Max