Support native simulator.

[zhang-wenchao]

https://docs.zephyrproject.org/latest/boards/native/native_sim/doc/index.html

[zhang-wenchao]

Rust llvm target x86_64-unknown-none，I actually tested it and it works.

[zhang-wenchao]

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 582e14a..26bf03d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -47,7 +47,8 @@ function(_rust_map_target)
message(FATAL_ERROR "Rust: Unsupported riscv ISA")
endif()
else()
-    message(FATAL_ERROR "Rust: Add support for other target")
+      set(RUST_TARGET "x86_64-unknown-none" PARENT_SCOPE)
+#    message(FATAL_ERROR "Rust: Add support for other target")
endif()
endfunction()

diff --git a/Kconfig b/Kconfig
index 9a3ed88..4c44422 100644
--- a/Kconfig
+++ b/Kconfig
@@ -8,7 +8,7 @@ menu "Rust Language Support"
config RUST_SUPPORTED
bool
default y if (CPU_CORTEX_M || \
-               (RISCV && !RISCV_ISA_RV32E && !RISCV_ISA_RV128I))
+               (RISCV && !RISCV_ISA_RV32E && !RISCV_ISA_RV128I) || ARCH_POSIX)
help
Selected for platforms that have support for Rust.

west build -p always -b native_sim/native/64

I'm trying to figure out how to support and Rust target.