where the path specified is relative to the toplevel glibc source
directory.
That has the wrong number of ../ components to achieve the desired
effect; it actually searches relative to include/ for a file that does
not exist there, then goes on to search the #include <> paths
specified with -I, eventually finding the desired file via such a path
(e.g. sysdeps/nptl/) with the right number of directory components.
Before that it searches include/../.. because of the -Iinclude,
meaning that an appropriately named file outside the glibc source tree
can affect the build.
This patch changes all those files to do #include <path> without the
../../, as some such files already do.