Building version without option, or with --with-openssl-dir=/usr --with-mongodb-sasl=/usr

$ php -d extension=modules/mongodb.so -v
PHP Warning: PHP Startup: Unable to load dynamic library 'modules/mongodb.so' - modules/mongodb.so: undefined symbol: _mongoc_sasl_set_service_host in Unknown on line 0
PHP 5.6.7 (cli) (built: Mar 19 2015 13:50:28)
...

Notice, fedora PHP build use RTLD_NOW instead of RTLD_LAZY, this can raise immediate load error, instead of runtime segfaults.