Solr for PHP gives "GLIBC_2.14 not found" error on Heroku

Question

Heroku does not support PHP officially, so I needed to add PHP extensions manually. I have created a php.ini file on my main directory:

extension_dir = "/app/www/ext/"
extension=mongo.so
extension=oauth.so
extension=solr.so

All the extension files are on the ext folder which is on the main directory also. Mongo and OAuth extensions are working perfectly but when Solr added, apache is giving me the error below:

PHP Warning:  PHP Startup: Unable to load dynamic library '/app/www/ext/solr.so' - /lib/libc.so.6: version `GLIBC_2.14' not found (required by /app/www/ext/solr.so) in Unknown on line 0

...and Solr extension is not working, obviously. I'm using Websolr add-on on Heroku and unfortunately neither Heroku nor Websolr is willing to help me about the issue. Heroku says "PHP is not officially supported," and Websolr says "ask Heroku."

So, any help will be appreciated.

Answer 1

It seems that there are no direct solutions but I have found a workaround. Instead of using solr.so extension, one can use open-source solr-php-client from here. It does note require a compiler, so no apache errors on Heroku.