glnx-shutil: Cope with ENOENT even after recursing to create parents

If we try to create `link/content` where `link` is a dangling symlink,
recursing to create `link` will succeed (mkdirat fails with EEXIST,
which is explicitly ignored), but then mkdirat for `link/content` will
still fail. Fail gracefully instead of crashing out with an assertion
failure.

Resolves: GNOME/libglnx#1
Signed-off-by: Simon McVittie <smcv@collabora.com>

glnx-shutil.c

@@ -149,12 +149,10 @@ mkdir_p_at_internal (int              dfd,
  again:
   if (mkdirat (dfd, path, mode) == -1)
     {
-      if (errno == ENOENT)
+      if (errno == ENOENT && !did_recurse)
         {
           char *lastslash;
 
-          g_assert (!did_recurse);
-
           lastslash = strrchr (path, '/');
           if (lastslash == NULL)
             {