Can't build ATM, due to this error (fixed, but ureleased): https://github.com/fifengine/fifengine/issues/1080

Perhaps a patch could be carried until the upstream makes a release again?

I don't get such error in a clean build environment. The repository doesn't even have a configure script in it.

Please try with a clean directory ( makepkg -Cc… ). Also try to change the build folder "$_githubname-$pkgver/build" in line 38, 47 and 51 to something like "$_githubname-$pkgver/aur-build" and try building again. That's a change I haven't pushed yet.

./configure: line 26302: syntax error near unexpected token newline'<br> ./configure: line 26302: '''
==> ERRORE: Si è verificato un errore in build().

Because the getchildren function is deprecated this package must been patched to work with Pytton3.9.

You can do this by adding the following sed commands to the prepare funktion of the PKGBUILB file or using this commit as patch.

sed -i 's/moduleTree\.getchildren():/moduleTree:/g'                   "./engine/python/fife/extensions/serializers/simplexml.py"
sed -i 's/self\._root_element\.getchildren():/self\._root_element:/g' "./engine/python/fife/extensions/serializers/simplexml.py"
sed -i 's/c\.getchildren():/c:/g'                                     "./engine/python/fife/extensions/serializers/simplexml.py"
Otherwise you get this error AttributeError: 'xml.etree.ElementTree.Element' object has no attribute 'getchildren' if you execute unknown-horizons.
[...]
==> Making package: fife 0.4.2-2 (Tue Jul  7 16:09:06 2020)
==> Checking runtime dependencies...
==> Missing dependencies:
  -> libstdc++5
==> Checking buildtime dependencies...
==> ERROR: Could not resolve all dependencies.
[...]
After installing libstdc++5 I got:
[...]
- Configuring done
CMake Error in CMakeLists.txt:
  Imported target "Boost::system" includes non-existent path
    "/include"
  in its INTERFACE_INCLUDE_DIRECTORIES.  Possible reasons include:
  * The path was deleted, renamed, or moved to another location.
  * An install or uninstall procedure did not complete successfully.
  * The installation package was faulty and references files it does not
  provide.
CMake Error in CMakeLists.txt:
  Imported target "Boost::system" includes non-existent path
    "/include"
  in its INTERFACE_INCLUDE_DIRECTORIES.  Possible reasons include:
  * The path was deleted, renamed, or moved to another location.
  * An install or uninstall procedure did not complete successfully.
  * The installation package was faulty and references files it does not
  provide.
-- Generating done
CMake Generate step failed.  Build files cannot be regenerated correctly.
==> ERROR: A failure occurred in build().
    Aborting...
[...]
            
The compilation fail due to deprecated/unsupported swig flags 
Modify the PKGBUILD file please to include this sed or create a patch 
build() {
  cd "$_githubname-$pkgver"
  [[ -d "build" ]] && rm -r "build"
  mkdir -p "build" && cd "build"
  cmake \
    -DCMAKE_INSTALL_PREFIX:PATH=/usr \
  sed -r -i 's/(-noproxydel|-fastinit|-fastunpack|-fastquery|-modernargs|-nobuildnone|-modern|-nosafecstrings)\b//g' CMakeFiles/fife*_swig_compilation.dir/build.make
  # If compilation seems to stall at 99% for ages, do not abort!
  # While not perfectly convenient, that is to be expected from
  # SWIG. Eventually, you'll reach the holy triple-digit land.