how to build separate tool alone?

[Vladimir Lebedev-Schmidthof]

Hello,

I've downloaded Android sources and they build fine by running make.
Though I'd like to make some changes to one specific tool, aapt for my
needs.
Though I can edit sources and rebuild all the platform, it takes loads
of time. I think having nice distributed build system it is somehow
possible to build just one tool? Also, build it in debug mode (adding
debug symbols in executable for later debugging).

How could I achieve it?

Thanks in advance.