BUILD_DEPENDS= RUN_DEPENDS=

[Bryan Drewery]

Hi,

I was trying to append to these in my /etc/make.conf and found that a
large (thousands) number of ports are using = instead of +=, thus
destroying any user-supplied depends.

The use case for wanting to do this is to force devel/ccache to be a
build dependency on all ports, for package building. Or to force in a
particular library along with LDFLAGS into particular ports. This is
achievable by modifying bsd.local.mk, but is not ideal.

This goes along with updating all CLFAGS/LDFLAGS to use += instead of =.

If there is no objection to this route, I will follow-up with a patch/PR
to update the ports and handbook.

Regards,
Bryan Drewery