Add signed type apr_intptr_t, because intptr_t is C99, and is not 
recognized by MSVC6.  Changed ODBC dbd driver to use apr_intptr_t.


git-svn-id: https://svn.apache.org/repos/asf/apr/apr/trunk@1557720 13f79535-47bb-0310-9956-ffa450edef68