Some of the installed libstdc++ header files use '#include_next' to
work around toolchain oddities that might cause loops in the
compiler. However, these also cause mistakes in locating header files
when there are multiple C libraries installed as '#include_next' often
ends up finding default C library header files.
It doesn't seem like this patch could be accepted upstream; there's a
long discussion about the use of include_next in these headers which I
cannot fully understand.
Signed-off-by: Keith Packard <keithp@keithp.com>
