newbie question about openembedded dependency tracking

[Ray Lehtiniemi]

hi all

just got my neo1973 and am getting up to speed on the build environment.  i am 
following the instructions at

  http://wiki.openmoko.org/wiki/Application_Development_Crash_Course

it seems like i have gotten the package built once.  however, i'm not sure 
about the dependency tracking...

i would expect that:

  # touch local/packages/myhelloworld/files/myhelloworld.c
  # make openmoko-devel-image

would notice that it needs to rebuild myhelloworld, but it doesn't.  am i 
expecting too much, or did i do something wrong?

thanks
ray