Following https://bugs.archlinux.org/task/76509, I'm reopening my pull request. Now I have 2 issues:

1. smpeg package have been updated to 2.0.0 which breaks fillets-ng dependency of smpeg (assuming is can be fixed to work):

checking for SMPEG_new in -lsmpeg... no
...
Checked components: X11=yes, WINDRES=no, FRIBIDI=yes, SMPEG=no
...
https://i.imgur.com/Qkkhlxo.png


2. Unpatched PKGBUILD gives me this error (I'm building on Manjaro ARM):

ScriptState.cpp: In constructor ‘ScriptState::ScriptState()’:
ScriptState.cpp:25:15: error: ‘lua_open’ was not declared in this scope; did you mean ‘lua_len’?
25 | m_state = lua_open();
| ^~~~~~~~
| lua_len
ScriptState.cpp: In member function ‘void ScriptState::prepareErrorHandler()’:
ScriptState.cpp:47:27: error: ‘LUA_GLOBALSINDEX’ was not declared in this scope
47 | lua_settable(m_state, LUA_GLOBALSINDEX);
| ^~~~~~~~~~~~~~~~
ScriptState.cpp: In member function ‘void ScriptState::insertErrorHandler(int)’:
ScriptState.cpp:57:25: error: ‘LUA_GLOBALSINDEX’ was not declared in this scope
57 | lua_rawget(m_state, LUA_GLOBALSINDEX);
| ^~~~~~~~~~~~~~~~
make[2]: *** [Makefile:359: ScriptState.o] Error 1
make[2]: *** Waiting for unfinished jobs....
make[2]: Leaving directory '/build/fillets-ng/src/fillets-ng-1.0.1/src/gengine'
make[1]: *** [Makefile:215: all-recursive] Error 1
make[1]: Leaving directory '/build/fillets-ng/src/fillets-ng-1.0.1/src'
make: *** [Makefile:285: all-recursive] Error 1
==> ERROR: A failure occurred in build().
Aborting...
==> ERROR: Building package [fillets-ng] failed.
Cleaning up.

The output above comes from a clean chroot as requested. aarch64 can be removed from PKGBUILD as noted.