Ah, PHP is the classic opensource package to have problems with. I have been having different issues since 4.0.4 - 4.0.6 was the first one I ever got to compile, and when I tried again later - it failed.
People will often blame AIX - but most of the problems I have had over they years have been resolved by fixes to libtool, or going back to an older version. Some of the patches specific for AIX have been wrong from a general point of view, and need fixing again.
PHP project is quite right in stating that it is not really a bug in PHP code. However, PHP has always been, for me, the most time-consuming package to bundle.
Speaking of, now that my vacation is finished I'll see how far I can get