Bug#1111643: openal-soft: FTBFS in a non-minimal environment (with libsdl3-dev installed)

[Simon McVittie]

Source: openal-soft
Version: 1:1.24.2-2
Severity: normal
Tags: patch fixed-upstream ftbfs
Forwarded: https://github.com/kcat/openal-soft/issues/1165

openal-soft fails to build from source if libsdl3-dev happens to be
installed (see upstream issue report for a full reproducer). I'm reporting
this as low-severity, since official buildds work in a minimal environment.

The attached patches fix the build in my environment (a Debian testing
derivative that has libsdl3-dev preinstalled, namely a possible future
branch of the Steam Runtime).

Thanks,
    smcv