Incremental configury refactoring.
Incremental configury refactoring.

* configure.in: Without further change, move some lines up and down in the
    file.
  Apache: Up above APR, as a preparatory step future changes regarding paying
    attention to what APR any found Apache is using when deciding on APR.
  Neon: Alongside APR, APR-util, so that the three bundled-source libraries
    are together.
  DB version AC_DEFINEs: Move to be close to where the corresponding shell
    variables are defined.
  Miscellaneous constant definitions: Collect together.
  $enable_debugging: Move action code to be with option detection code.

jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion