This patch basically overrides the broken 2.59 macro with the fixed 2.6
one. I have successfully reproduced the problem and then applied the
patch and gotten the build to work so I would like to propose that we
check in Ralf's patch to newlib. I considered whether we should put
confsubdir.m4 in the config directory instead of the newlib directory in
case any other tools needed it but none of the 106 newlib Makefile.am
files list the config directory in their ACLOCAL_AMFLAGS flags and I
don't want to change them all so I dropped that idea.