PHP version 5.2.11 or later is required.

The libxml and curl extensions must also be enabled for the Apache Solr extension to be available.

libxml2 2.6.31 or later is required.

libcurl 7.18.0 or later is also required.

The above library versions are required and attempting to hack the code to make it compile is strongly discouraged. It will fail, possibly with errors that could be hard to debug