PHP API, PHP Extension, Zend Extension Build and "outdated" dates

When viewing phpinfo() after a fresh build of PHP I saw dates on 
the following sections that did not match the date I built PHP from source:

- PHP API
- PHP Extension
- Zend Extension
- Zend Extension Build 

The dates were 4(!) years back and all the same, so I thought something may 
be wrong with the build directories. WRONG! The dates are OK.

To check if the dates are up-to-date, go to PHP source directory (the root 
when the phpXXXXX.tar.gz file is extracted to and look into Zend/zend_modules.h. 
Find this line:

#define ZEND_MODULE_API_NO 20081109

The date there should be the same as on phpinfo().

Same thing about "wrong" extension directory, which are padded with 
non-zts-non-debug-200081109 etc. It's correct... for some reason.