[falcolas]

It's not a requirement - I give you: .RECIPEPREFIX

> If you prefer to prefix your recipes with a character other than tab, you can set the .RECIPEPREFIX variable to an alternate character

That said, how hard is it really to disable tab expansion in your editor? I have a block of configuration dedicated to the different indentation requirements of different programming and configuration languages. In more modern editors, I don't even have to do anything at all to edit Makefiles with tabs - they come pre-configured to do the right thing.