apache2-prefork-dev 2.2.17-1ubuntu1.2 (armel binary) in ubuntu natty

 This package provides the development headers and apxs2 binary for
 apache2-mpm-prefork; see the apache2 package description for more details.
 .
 This should only be used when you absolutely *must* support a non-threaded
 environment (for PHP, for example).