configure

Setting CONFIGURE_STYLE to "gnu" will cause the build process to run a port's configure script prior to building the port.  This will detect dependencies.

It's very important to monitor the output of the configure script to find any problems that might need to be patched, any dependencies that may need to be added to the Makefile and any unexpected dependencies that configure may find.

Sometimes, if the configure script is looking for a specific dependency and it is installed on your system, you may have to explicitly prevent the port from using it by either using "--disable-foo" in CONFIGURE_ARGS or patching the configure script.  These are called hidden dependencies.

It's usually a good idea to use portslogger when running make configure to have a logfile to review for debugging purposes.