I've got a failure while trying to compile with "-mmacosx-version-min=10.7" since MAC_OS_X_VERSION_MAX_ALLOWED is greater than MAC_OS_X_VERSION_10_15 but still we can't use `aligned_alloc` since of the lower bound (10.7).
I'm not sure about internal details of how `__OSX_AVAILABLE` works, but my hope is the it would only make this interpose available starting from the OS version specified.
Also, it helps me to compile mimalloc with "-mmacosx-version-min=10.7".