Possible NOTE on clang + ubuntu

[paleolimbot]

Found doing reverse dependency checks for wk on docker pull paleolimbot/r-debug:

File ‘s2/libs/s2.so’:
      Found ‘stderr’, possibly from ‘stderr’ (C)
        Object: ‘absl/strings/internal/str_format/parser.o’
    
    Compiled code should not call entry points which might terminate R nor
    write to stdout/stderr instead of to the console, nor use Fortran I/O
    nor system RNGs.
    
    See ‘Writing portable packages’ in the ‘Writing R Extensions’ manual.