Successful build - Chance fights ever on the side of the prudent.

Link to build: https://jenkins.wildfiregames.com/job/docker-differential/358/display/redirect

• The flag was introduced in rP10534, all files touched in that commit are addressed.
• source/tools/dist/0ad.nsi and source/tools/dist/build.sh don't need a change
• extern_libs5.lua, clean-workspaces.sh, build-osx-libs.sh had been updated correctly
• found source/nvtt/patches/arm64-fix.patch having an empty hunk for libraries/source/spidermonkey/mozjs-31.2.0.rc0.tar.bz2 from rP16872, but it looks like it's ignored when applying. NVTT needs some attention anyhow I suppose.
• still had old mozjs shared libraries around: source/spidermonkey/lib/libmozjs38-ps-debug.so, libmozjs38-ps-release.so.
• Checked all folders that contains one of the files touched in that commit or mentioned here. In particular build/, grep for spider -i and mozjs.
• Found an unrevisioned symlink-libs.py in my osx/ folder, it seems to come from D1483 which I don't recollect applying. As it's not a revisioned file, it shouldn't be an issue. The header is the same as in build-osx-libs.sh.
• dehydra/printf-type-check.js also has something hardcoded about SpiderMonkey, but doesn't seem to need an update:

// SpiderMonkey:
if (name == 'JS_ReportError')
    return ['a', 'printf', 2, 3];
else if (name == 'JS_ReportWarning')
    return ['a', 'printf', 2, 3];

but should be remembered in case those two functions change.