NUMARRAY_INC_DIR is now constructed from NUMARRAY_HOME in the following
prioritized way depending upon the existance of directories:
NUMARRAY_INC_DIR=$NUMARRAY_HOME/include/python2.4
NUMARRAY_INC_DIR=$NUMARRAY_HOME/include/python2.3
NUMARRAY_INC_DIR=$NUMARRAY_HOME/include/python
Additionally, NUMARRAY_INC_DIR can now be input directly. NUMARRAY_HOME
is only used to set NUMARRAY_INC_DIR.
Note, the new method now conforms to what the numarray installer
actually does.