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

reporter_name="Yann Diorcet <diorcet.yann@gmail.com>"

reporter_url=""

reporter_comment="Config to build cross-compiler with mingw as kernel type for

32 bits Windows target"