[PATCH] posix: Avoid a stack overflow when glob is given many trailing slashes [BZ #30635]

[Bruno Haible]

Hi Collin,

> There is also https://sourceware.org/bugzilla/show_bug.cgi?id=33537,

Your fix of [BZ #30635] fixes this one as well, AFAICS from testing within
Gnulib. So, it's the same bug, but you might want to adjust the comment
in posix/glob.c and maybe add a second test case.

Bruno