[GNC] Error building 5.9 on Ubuntu 20.04

[Tim Kallmer]

I'm stuck and in need of help trying to build 5.9.
The command "cmake -DCMAKE_INSTALL_PREFIX=$HOME/.local ../gnucash-5.9"
fails with this:

-- Checking for module 'gwenhywfar>=5.6.0'
--   Requested 'gwenhywfar >= 5.6.0' but version of gwenhywfar is 5.1.3
CMake Error at /usr/share/cmake-3.16/Modules/FindPkgConfig.cmake:463
(message):
  A required package was not found
Call Stack (most recent call first):
  /usr/share/cmake-3.16/Modules/FindPkgConfig.cmake:643
(_pkg_check_modules_internal)
  CMakeLists.txt:399 (pkg_check_modules)
-- Configuring incomplete, errors occurred!

With "sudo apt install gwenhywfar-tools libgwenhywfar79
libgwenhywfar-core-dev" I get:

gwenhywfar-tools is already the newest version (5.1.3-1build1).
libgwenhywfar-core-dev is already the newest version (5.1.3-1build1).
libgwenhywfar79 is already the newest version (5.1.3-1build1).

With "sudo apt install libgwenhywfar60-dev" I get:

Package libgwenhywfar60-dev is not available, but is referred to by another
package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source
However the following packages replace it:
  libgwenhywfar-core-dev libgwengui-qt5-dev libgwengui-fox16-dev

With "sudo apt install libgwenhywfar-core-dev libgwengui-qt5-dev
libgwengui-fox16-dev" I get:

libgwengui-fox16-dev is already the newest version (5.1.3-1build1).
libgwengui-qt5-dev is already the newest version (5.1.3-1build1).
libgwenhywfar-core-dev is already the newest version (5.1.3-1build1).

I'm not sure what to do and now cannot seem to get 4.9 that I was using
previously to build again without errors. I'm stuck. Any suggestions?