Fix propagation of ${OPTIM} to subdirectories (which used to work in

early 1.3's at least), so that it is possible to do a
  make OPTIM=-g
from the src/ directory to temporarily override the default
(e.g., for debugging).


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/1.3.x@95060 13f79535-47bb-0310-9956-ffa450edef68