nios2-elf MingW

I made some progress on it, just have a problem now with building libstdc++

seems that it can not find the file cstddef, but the file is available

make: Entering directory `/c/nios2-src-6.1/gcc/build/nios2-elf/mcustom-fpu-cfg=60-1/libstdc++-v3/libsupc++'
/bin/sh ../libtool --tag CXX --tag disable-shared --mode=compile /c/nios2-src-6.1/gcc/build/gcc/xgcc -shared-libgcc -B/c/nios2                                                      -src-6.1/gcc/build/gcc/ -nostdinc++ -L/c/nios2-src-6.1/gcc/build/nios2-elf/mcustom-fpu-cfg=60-1/libstdc++-v3/src -L/c/nios2-sr                                                      c-6.1/gcc/build/nios2-elf/mcustom-fpu-cfg=60-1/libstdc++-v3/src/.libs -Bc:/nios2-6.1/nios2-elf/bin/ -Bc:/nios2-6.1/nios2-elf/l                                                      ib/ -isystem c:/nios2-6.1/nios2-elf/include -isystem c:/nios2-6.1/nios2-elf/sys-include  -mcustom-fpu-cfg=60-1 -I/c/nios2-src-                                                      6.1/gcc/libstdc++-v3/../gcc -I/c/nios2-src-6.1/gcc/build/nios2-elf/mcustom-fpu-cfg=60-1/libstdc++-v3/include/nios2-elf -I/c/ni                                                      os2-src-6.1/gcc/build/nios2-elf/mcustom-fpu-cfg=60-1/libstdc++-v3/include -I/c/nios2-src-6.1/gcc/libstdc++-v3/libsupc++ -O2 -g                                                       -O2 -g -O2  -mcustom-fpu-cfg=60-1 -fno-implicit-templates  -Wall -W -Wwrite-strings -Wcast-qual  -fdiagnostics-show-location=                                                      once    -c -o del_op.lo ../../../../../libstdc++-v3/libsupc++/del_op.cc
/c/nios2-src-6.1/gcc/build/gcc/xgcc -shared-libgcc -B/c/nios2-src-6.1/gcc/build/gcc/ -nostdinc++ -L/c/nios2-src-6.1/gcc/build/                                                      nios2-elf/mcustom-fpu-cfg=60-1/libstdc++-v3/src -L/c/nios2-src-6.1/gcc/build/nios2-elf/mcustom-fpu-cfg=60-1/libstdc++-v3/src/.                                                      libs -Bc:/nios2-6.1/nios2-elf/bin/ -Bc:/nios2-6.1/nios2-elf/lib/ -isystem c:/nios2-6.1/nios2-elf/include -isystem c:/nios2-6.1                                                      /nios2-elf/sys-include -mcustom-fpu-cfg=60-1 -I/c/nios2-src-6.1/gcc/libstdc++-v3/../gcc -I/c/nios2-src-6.1/gcc/build/nios2-elf                                                      /mcustom-fpu-cfg=60-1/libstdc++-v3/include/nios2-elf -I/c/nios2-src-6.1/gcc/build/nios2-elf/mcustom-fpu-cfg=60-1/libstdc++-v3/                                                      include -I/c/nios2-src-6.1/gcc/libstdc++-v3/libsupc++ -O2 -g -O2 -g -O2 -mcustom-fpu-cfg=60-1 -fno-implicit-templates -Wall -W                                                       -Wwrite-strings -Wcast-qual -fdiagnostics-show-location=once -c ../../../../../libstdc++-v3/libsupc++/del_op.cc -o del_op.o
In file included from ../../../../../libstdc++-v3/libsupc++/del_op.cc:31:
../../../../../libstdc++-v3/libsupc++/new:41:19: cstddef: No such file or directory
In file included from ../../../../../libstdc++-v3/libsupc++/del_op.cc:31:
../../../../../libstdc++-v3/libsupc++/new:82: error: declaration of `operator new' as non-function
../../../../../libstdc++-v3/libsupc++/new:82: error: `size_t' is not a member of `std'
../../../../../libstdc++-v3/libsupc++/new:82: error: expected `,' or `;' before "throw"
../../../../../libstdc++-v3/libsupc++/new:83: error: declaration of `operator new ' as non-function
../../../../../libstdc++-v3/libsupc++/new:83: error: `size_t' is not a member of `std'
../../../../../libstdc++-v3/libsupc++/new:83: error: expected `,' or `;' before "throw"
../../../../../libstdc++-v3/libsupc++/new:86: error: declaration of `operator new' as non-function
../../../../../libstdc++-v3/libsupc++/new:86: error: `size_t' is not a member of `std'
../../../../../libstdc++-v3/libsupc++/new:86: error: expected primary-expression before "const"
../../../../../libstdc++-v3/libsupc++/new:86: error: expected `,' or `;' before "throw"
../../../../../libstdc++-v3/libsupc++/new:87: error: declaration of `operator new ' as non-function
../../../../../libstdc++-v3/libsupc++/new:87: error: `size_t' is not a member of `std'
../../../../../libstdc++-v3/libsupc++/new:87: error: expected primary-expression before "const"
../../../../../libstdc++-v3/libsupc++/new:87: error: expected `,' or `;' before "throw"
../../../../../libstdc++-v3/libsupc++/new:92: error: declaration of `operator new' as non-function
../../../../../libstdc++-v3/libsupc++/new:92: error: `size_t' is not a member of `std'
../../../../../libstdc++-v3/libsupc++/new:92: error: expected primary-expression before "void"
../../../../../libstdc++-v3/libsupc++/new:92: error: expected `,' or `;' before "throw"
../../../../../libstdc++-v3/libsupc++/new:93: error: declaration of `operator new ' as non-function
../../../../../libstdc++-v3/libsupc++/new:93: error: `size_t' is not a member of `std'
../../../../../libstdc++-v3/libsupc++/new:93: error: expected primary-expression before "void"
../../../../../libstdc++-v3/libsupc++/new:93: error: expected `,' or `;' before "throw"
make: ***  Error 1

Any idea?

stefaan@PC160 /c/nios2-src-6.1/gcc/build/nios2-elf/mcustom-fpu-cfg=60-1/libstdc++-v3/include
$ ls
Makefile   clocale  cwchar      istream    set                    stamp-std
algorithm  cmath    cwctype     iterator   sstream                stdexcept
backward   complex  debug       limits     stack                  streambuf
bits       csetjmp  deque       list       stamp-backward         string
bitset     csignal  ext         locale     stamp-bits             utility
cassert    cstdarg  fstream     map        stamp-c_base           valarray
cctype     cstddef  functional  memory     stamp-c_compatibility  vector
cerrno     cstdio   iomanip     nios2-elf  stamp-debug
cfloat     cstdlib  ios         numeric    stamp-ext
ciso646    cstring  iosfwd      ostream    stamp-host
climits    ctime    iostream    queue      stamp-nios2-elf