3 How to build a file in the current directory without traversing the whole tree?

Suppose I have index.tex that I want to build it to index.htm to try something but it is allready update to date. But if I do make clean it will now clean everything down the whole tree, which is not what I want.

I can touch index.tex then do make. But I can also use -B option and give it the target to build, like this

make -I$HOME -B index.htm