A new mysql_config detection was added to 1.7.17, so look during configure for something along the lines of:
checking for mysql_config... [answer]
checking whether mysql_config produces valid results.. [answer]
If the latter says no, then check config.log for "mysql_config" and any compilation errors when it tries the second mysql_config check, and also the output of mysql_config --cflags
If you need help with that, just post them here and either Rob or GD will be able to advise i'm sure
