Anyway, I parsed the file manually, and the version listed is 1.4.3.
Not sure how to correct the problem, but there's almost certainly something wrong with the libtool that's part of your apache installation. If it's giving the right flags to gcc, you should not see warnings about the _start or main functions. Those are only used when linking an executable application. They should not be referenced in a shared object, such as mod_auth_pam.
