graphics/libEGL has merged into
graphics/mesa-libs on may 12ves 2017
One can find such info in text file /usr/ports/UPDATING
or even
make -C /usr/ports/ search name="libEGL"
and you will get the confirmation
So first remove the old package with
pkg delete -f libEGL
and install mesa-libs
make -C /usr/ports/graphics/mesa-libs reinstall clean
Check if there is no other missing dependencies with
pkg check -d
Either this command will show some missing dependencies, either when a given dependency is hardly updated, sometimes it is necessary to relink ports which depends on this dependency showing a broken link through this command.
Some administrators will say that one should always rebuild such port on a dependency update, but they can do that, they have powerful server. They can automate the process and make run that at delayed date.
A simple desktop user generally use
ports-mgmt/portupgrade or
ports-mgmt/portmaster, and it is sufficient in most of case.
There are possibly other merged ports in mesa-libs, I can't remember, but process is the same.
It could be wise to update your system port at less.... let's say one time per month, and frankly I think one time per week would be a good measure
and check from time to time the base system :
freebsd-update fetch
.... each week
Security flaws may occur on ports as on base system, FreeBSD is safer than Windows, but under the condition that user complies with some minimum rules of security.
As a comparison, there is on a common Linux Desktop generally one small update per week