Hello,
I have the problems to compile 4.2.1 (with ./configure
which worked < 4.2.X)

gcc -I. -I/var/log/ovh/php-4.2.1/ext/domxml -I/var/log/ovh/php-4.2.1/main -I/var/log/ovh/php-4.2.1 -I/var/log/ovh/php-4.2.1/Zend -I/usr/local/ssl/include -I//include -I/usr/local/include -I/usr/local/BerkeleyDB.3.3/include -I/usr/include/libxml2 -I/usr/local/include/freetype -I/usr/local/include/imap -I/usr/include/mysql  -I/var/log/ovh/php-4.2.1/TSRM -g -O2  -c php_domxml.c && touch php_domxml.lo
php_domxml.c: In function `zif_domxml_doc_get_element_by_id':
php_domxml.c:2675: warning: passing arg 2 of `xmlHashScan' from incompatible pointer type
php_domxml.c: In function `zif_domxml_doc_ids':
php_domxml.c:3292: warning: passing arg 2 of `xmlHashScan' from incompatible pointer type
php_domxml.c: In function `zif_xmldoc':
php_domxml.c:3309: `xmlDoValidityCheckingDefaultValue' undeclared (first use in this function)
php_domxml.c:3309: (Each undeclared identifier is reported only once
php_domxml.c:3309: for each function it appears in.)
php_domxml.c:3325: `xmlLoadExtDtdDefaultValue' undeclared (first use in this function)
make[3]: *** [php_domxml.lo] Error 1
make[3]: Leaving directory `/var/log/ovh/php-4.2.1/ext/domxml'
make[2]: *** [all-recursive] Error 1
make[2]: Leaving directory `/var/log/ovh/php-4.2.1/ext/domxml'
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory `/var/log/ovh/php-4.2.1/ext'
make: *** [all-recursive] Error 1