I upgraded from 3.22.0a to 3.22.3 and it worked just fine.
Whenever I make the CGI version or compile Apache with mysql included it will fail:

/usr/local/lib/mysql/libmysqlclient.a(libmysql.o): In function
`mysql_real_connect':
/usr/local/mysql-3.22.3-alpha/client/libmysql.c:832: undefined reference
to `gethostbyname_r'
make: *** [php] Error 1

Some manipulation to the function_entries doesn't help (I mapped to
mysql_connect). 

>From the Docs:

Upgrading to 3.22 from a 3.21 version.
--------------------------------------

   The C interface to mysql_real_connect() has changed.  If you have an
old client program that calls this, you must place a 0 for the new DB
argument (or recode the client to send the db element for faster
connections).

Changes in release 3.22.1
-------------------------

   * Added new API functions: mysql_init() and mysql_options().  One
     MUST now call mysql_init() before one calls mysql_real_connect().
     One doesn't have to call mysql_init() if one only uses
     mysql_connect().

-Egon