Allow reordered MAKEFLAGS

-R and -r (-Rr) can be reordered to -r and -R (-rR).
This happens with MSYS1/2 gnu-make and mingw32-make,
and triggers "Recursion detected, bailing out..."

Signed-off-by: Ray Donnelly <mingw.android@gmail.com>
Message-Id: <CAOYw7dsdsg-XaDOwwEWJeUUSo2Vu_UD5GtkSgNTu59ai7yx0cQ@mail.gmail.com>
Patchwork-Id: 258027

 python

 import sys

 sys.path.insert(0, '@@PREFIX@@/share/gcc-@@VERSION@@/python')

 from libstdcxx.v6.printers import register_libstdcxx_printers

 register_libstdcxx_printers (None)

 end