[cmake] Temporarily disable building std::filesystem in CrossWinToARMLinux.cmake

Author: broadwaylamb

clang/cmake/caches/CrossWinToARMLinux.cmake

@@ -89,6 +89,9 @@ set(LIBCXXABI_LINK_TESTS_WITH_SHARED_LIBCXX    OFF CACHE BOOL "")
 set(LIBCXX_LINK_TESTS_WITH_SHARED_LIBCXXABI    OFF CACHE BOOL "")
 set(LIBCXX_LINK_TESTS_WITH_SHARED_LIBCXX       OFF CACHE BOOL "")
 
+# FIXME: Remove this when https://reviews.llvm.org/D78200 is merged.
+set(LIBCXX_ENABLE_FILESYSTEM OFF CACHE BOOL "") 
+
 set(LIBCXX_USE_COMPILER_RT                  ON CACHE BOOL "")
 set(LIBCXX_TARGET_TRIPLE                    "${CMAKE_C_COMPILER_TARGET}" CACHE STRING "")
 set(LIBCXX_SYSROOT                          "${DEFAULT_SYSROOT}" CACHE STRING "")