libx264: Fix use of self_settings_build

[Ahajha]

In this PR, self._settings_build was introduced, but not defined. I'm not certain how it passed CI, but this should be self.settings_build.

Fixes #26098

[valenotary]

Thanks @Ahajha ! yeah im curious how this passed CI in the first place...

[Ahajha]

My only guess is that the branch in question is only for Android, so maybe it just got skipped over.

[uilianries]

@Ahajha Hello! Thank for providing this hotfix quickly. Indeed I made some mistake when pushing that PR, because my build logs were working fine when cross-building from Linux to Android (see https://gist.github.com/uilianries/f3ca036501f9c175312fb7c7df614db2). Probably I forgot to push more code 😞 . I just checked locally again and current recipe in the master branch is broken for Android (log below) and when applying your fix, it's working fine again.

Current build log (master branch): libx264-cci.20240224-android-static.log

PR build log (commit d5c3d11): libx264-cci.20240224-android-static-pr.log

[uilianries]

The _settings_build is no longer needed, because is an idiom used for Conan 1.x when building using a single profile (before Conan 1.24). The settings_build should be always available.

[ErniGH]

Thank you for fixing this issue! Your help is greatly appreciated. 😊