i'll answer myself (FINALLY!)
current "configure options" can be viewed with "php-config" shell script, aside with other compile time options too =D!!! ...
in some distributions it comes with the "php-devel" package... but until in this online manual "php-config" is mentioned in pecl extensions documentation (i couldn't find on pecl site), idk if that "php-devel" has something to do with this
... however i noticed they are literal strings inside the script, i hope the script itself were built together with php compilation o_O
in the previous page "configure options" (link shown above ^), there is an editor note with additional info about it