revret 1533105


git-svn-id: https://svn.apache.org/repos/asf/apr/apr/branches/1.5.x@1533107 13f79535-47bb-0310-9956-ffa450edef68
Merge r1533104 from trunk:

it should really handle src==NULL 

Reviewed/backported by: jim


git-svn-id: https://svn.apache.org/repos/asf/apr/apr/branches/1.5.x@1533108 13f79535-47bb-0310-9956-ffa450edef68