By default, use the same CC and CPP with which APR was built.

The user can override with CC and CPP environment variables.

This applies to out-of-tree APR builds.  Prior to this change,
if you had multiple compilers on the system and you told
APR to use a non-default one, you'd have to remember to tell
Apache too.  Otherwise, Apache would use the default compiler
but use CFLAGS that went with the compiler that APR was built
with.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@99572 13f79535-47bb-0310-9956-ffa450edef68