A quick note to anyone building PHP with cURL or http extension support as well as one of the MySQL extensions (mysql, mysqli and pdo_mysql). The MySQL binaries found on mysql.com are built against yaSSL as opposed to the more common openssl against which libcurl (usede by cURL and HTTP extensions) is linked. The conflict between the two libraries causes curl initialization of the SSL layer to fail preventing startup of the PHP extensions.
To fix this problem you can either use older mysqlclient binaries (5.0.18 works) or compile MySQL yourself against openssl, either of these two will allow a working build of PHP with MySQL and curl support.