subdir-objects AM Option needed during build

[sudheesh001]

Thank you for the great library. I've had a little initial trouble setting this up because of the subdir-objects option is disabled. Adding the patch in the autoconf file as follows helped me generate the required ./configure file and build the library. I'd be happy to send this in as a patch if its necessary.

-AM_INIT_AUTOMAKE
+AM_INIT_AUTOMAKE([subdir-objects])