questions about ports

[Severe Grind]

Hello,

I have several questions concerning creating Makefile
I don't  understand in what sequence USE_* flags in Makefile are processed,
for example - in archives/jzlib/Makefile add
USE_APACHE=22, before
USE_JAVA=    yes
USE_JAVA=    1.4+
but when i execute make install, first install JAVA.

Is it possible through the Makefile to make the following:
In pre-fetch  stage makes dependences on flags:
USE_AUTOTOOLS
USE_JAVA
USE_APACHE
after that execute script, pre-configure which will make firebird-2.1 from
sorce, then make PHP via USE? Or, it can be done by FETCH_DEPENDENDS etc.?