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