Why do we create a broken symlink for include/bits/stamp-bits ?

[Jonathan Wakely]

In include/Makefile the stamp-bits-sup target creates a symlink called
stamp-bits:

stamp-bits-sup: stamp-bits ${bits_sup_headers}
	@-cd ${bits_builddir} && $(LN_S) $? . 2>/dev/null
	#                        ^^^^^^^^^^^^
	@$(STAMP) stamp-bits-sup

Should this use "$(LN_S) ${bits_sup_headers} ." instead, so it only
creates symlinks for the headers, not "stamp-bits" as well?

The broken symlink isn't a big deal but causes errors like:

libstdc++-v3$ grep -R foobar include/
grep: include/bits/stamp-bits: Too many levels of symbolic links