Octave broken again, Error: Dependency 'gfortran' not found.

[neilt (Neil Tiffin)]

neils-iMac:~ neil$ sudo port selfupdate
--->  Updating MacPorts base sources using rsync
MacPorts base version 2.5.0 installed,
MacPorts base version 2.5.0 downloaded.
--->  Updating the ports tree
--->  MacPorts base is already the latest version

The ports tree has been updated. To upgrade your installed ports, you should run
  port upgrade outdated
neils-iMac:~ neil$ port outdated
The following installed ports are outdated:
octave                         4.2.2_1 < 4.4.0_2         
octave-control                 3.1.0_1 < 3.1.0_2         
octave-general                 2.1.0_0 < 2.1.0_1         
octave-io                      2.4.11_0 < 2.4.11_1       
octave-miscellaneous           1.2.1_3 < 1.2.1_4         
octave-nan                     3.1.4_1 < 3.1.4_2         
octave-optim                   1.5.2_3 < 1.5.2_4         
octave-signal                  1.4.0_0 < 1.4.0_1         
octave-specfun                 1.1.0_3 < 1.1.0_4         
octave-struct                  1.0.15_0 < 1.0.15_1       
octave-tisean                  0.2.3_3 < 0.2.3_4         
octave-tsa                     4.4.5_3 < 4.4.5_4         
py36-oct2py                    4.0.6_0 < 4.0.6_1         
py36-octave_kernel             0.28.3_2 < 0.28.3_3       
neils-iMac:~ neil$ sudo port upgrade octave
Warning: No port gfortran found in the index.
--->  Computing dependencies for mpich-default
Error: Dependency 'gfortran' not found.
Error: Problem while installing mpich-default
Error: Follow https://guide.macports.org/#project.tickets to report a bug.

[MarcusCalhoun-Lopez (Marcus Calhoun-Lopez)]

Duplicate of #56582.