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

# Compute AVR32-specific values

CT_DoArchTupleValues() {

    # gcc ./configure flags

    CT_ARCH_WITH_ARCH=

    CT_ARCH_WITH_ABI=

    CT_ARCH_WITH_CPU=

    CT_ARCH_WITH_TUNE=

    CT_ARCH_WITH_FPU=

    CT_ARCH_WITH_FLOAT=

    CT_TARGET_SYS=none

}