for those being interested:
MediaWiki trunk works with PHP 5.3.8 (also with Extension:OpenID)
# ./configure '--prefix=/usr' '--datadir=/usr/share/php'
'--mandir=/usr/share/man' '--bindir=/usr/bin' '--libdir=/usr/share'
'--includedir=/usr/include' '--sysconfdir=/etc' '--with-libdir=lib64'
'--with-config-file-path=/etc' '--with-exec-dir=/usr/lib64/php/bin'
'--with-apxs2=/usr/sbin/apxs2-prefork' '--with-openssl' '--with-bz2'
'--with-zlib' '--with-curl' '--with-ldap' '--with-mysql' '--enable-soap'
'--enable-mbstring' '--with-xsl' '--enable-calendar' '--with-gd'
'--with-iconv' '--with-pspell' '--with-gmp' '--with-mcrypt' '--enable-zip'
# make
# make install
# libtool --finish /usr/local/src/php-5.3.8/libs