I ran this checker for the upcoming Invision Powerboard 3.0
Quote:
IP.Board 3.0 Requirements Checker
Checking for mysqli support...FAIL
The mysqli extension is preferred over the original mysql extension. If you are utilizing another database driver (such as MSSQL) you can ignore this message. This is not a requirement, but if possible we recommend you to install the mysqli extension for better performance.
I thought the php is already compiled with support for mysqli with the following parameters.
Then I think mysqli has not built into PHP binary or load as a module, you can try build PHP again and check the log file to make sure there is no error regarding this.