Freeciv

clang_debug job would start failing if we merged autotools lua-5.5 patch #1570

lua build gives warnings that we cannot fix on clang. With lua-5.4 we work around that by using syslua instead of building lua. With lua-5.5 that won't be possible until we have a runner that has lua-5.5 in it, likely next summer once github provides ubuntu-26.04 runners.

One solution would be to override -Werror of --enable-debug with -Wno-error, which of course means that the job starts succeeding with any warnings, not just those of lua.