Problem with ./feeds update -a

After editing the Makefile for a certain package, I receive following error.
What to do, to make shure, my change to Makefile is kept during update, but all other packages are updated ?

 ./scripts/feeds update -a
Updating feed 'packages' from '' ...
remote: Counting objects: 779, done.
remote: Compressing objects: 100% (508/508), done.
remote: Total 779 (delta 424), reused 564 (delta 225)
Receiving objects: 100% (779/779), 184.41 KiB | 0 bytes/s, done.
Resolving deltas: 100% (424/424), completed with 114 local objects.
   14ad4cb..52ca8c9  master     -> origin/master
Updating 7673d1e..52ca8c9
error: Your local changes to the following files would be overwritten by merge:
Please, commit your changes or stash them before you can merge.
Updating feed 'luci' from '' ...

Easiest is probably managing the feeds with git manually rather than with the script. Branching then rebasing would be one good approach.

It might go something like this (please read the docs, this is so you have an idea where to start!).

Create your own branch and add your changes to it

[.../openwrt/feeds/packages]$ git checkout -b some-name-of-yours
[.../openwrt/feeds/packages]$ git add net/squid
[.../openwrt/feeds/packages]$ git commit

Add more changes

[.../openwrt/feeds/packages]$ git add net/squid
[.../openwrt/feeds/packages]$ git commit

Get the changes from upstream

[.../openwrt/feeds/packages]$ git fetch

And make your changes "start with" the current version

[.../openwrt/feeds/packages]$ git rebase origin/master