Easy enough (assuming $SRC is your list of source files and 'all' is top level target) 'make watch' could do this

   watch:
        while ! inotifywait -e modify $(SRC) ; do time -p make all; done

If you care for it, fswatch is cross-platform:

https://github.com/emcrisostomo/fswatch

something along the lines of inotify:

http://man7.org/linux/man-pages/man1/inotifywait.1.html

or just use tup

http://gittup.org/tup/

Also, entr

http://entrproject.org

There's "when-changed" in pip.

    pip install when-changed
    when-changed *.tex -c "make all && echo 'done'"

Then you can make rule in your make file called "watch" or "build-server" which calls that command, so you just need to write "make watch".

It's trivial to roll your own: https://github.com/gall0ws/watch