arch/risc-v/src/cmake/Toolchain.cmake: Msys2 CMake fixed nuttx/config.h: No such file or directory

[simbit18]

Summary

fixed
/qemu-rv/qemu_rv_head.S:25:10: fatal error: nuttx/config.h: No such file or directory
25 | #include <nuttx/config.h>
| ^~~~~~~~~~~~~~~~
compilation terminated.

added

# override the responsible file flag

if(CMAKE_GENERATOR MATCHES "Ninja")
  set(CMAKE_C_RESPONSE_FILE_FLAG "$DEFINES $INCLUDES $FLAGS @")
  set(CMAKE_CXX_RESPONSE_FILE_FLAG "$DEFINES $INCLUDES $FLAGS @")
  set(CMAKE_ASM_RESPONSE_FILE_FLAG "$DEFINES $INCLUDES $FLAGS @")
endif()

same arm issue #14892

Impact

Impact on user: No changes to user-facing functionality
Impact on build: Build process remains the same

Testing

local msys2
cmake -B build -DBOARD_CONFIG=rv-virt:nsh -GNinja
cmake -B build -DBOARD_CONFIG=rv-virt:nsh64 -GNinja

[simbit18]

@lupyuen @xiaoxiang781216 perhaps it is better to stop rv-virt/citest

Configuration/Tool: rv-virt/citest is leech of Linux (risc-v-05) !!!

test_open_posix/test_openposix_.py::test_ltp_interfaces_pthread_mutexattr_setpshared_1_1 Killing pytest after timeout...
Terminated
  Normalize rv-virt/citest
HEAD detached at pull/14961/merge
Untracked files:
  (use "git add <file>..." to include in what will be committed)
	boards/risc-v/qemu-rv/rv-virt/configs/citest/logs/
	fatfs.img

nothing added to commit but untracked files present (use "git add" to track)
====================================================================================

unrelated by this PR

[xiaoxiang781216]

should be fixed by #14950, so let's merge this patch directly.