How to patch, build and debug PHP extension : PDO Firebird

Vjacheslav V. Borisov wrote a tutorial on how to build and debug PDO Firebird driver :

I noticed that there is too many bugs open and too few developers who can
do the work.
And even this list is almost dead. Don’t know what is the cause of that,
but may be it is just hard to start ?
I recently written some patches for php – work, which I never done before.
And i can say, this really not so hard, if you know C/C++ (or at least
php?) and linux.
Most troublesome work is to setup build environment, so i decided to write
instruction how to patch, build and debug PHP extension, so may be more web
developers can contribute to php.