The entire source code tree should be positioned in a location where every application that needs it can access it. There is no provision for standard include files and normally it's much to difficult for users to match versions to use it as a shared library. Those of you who were around in 1997 may remember QT doing this.
Run make. Make automatically configures itself. The output is put in i686/libquicktime.a. You should manually set the CFLAGS environment variable with the optimum optimization parameters for your i686 derivative.