Update std atomic check and simd compatibility check for arc compiler (#3716)

core/iwasm/compilation/aot_llvm.c

@@ -3121,7 +3121,8 @@ aot_create_comp_context(const AOTCompData *comp_data, aot_comp_option_t option)
 #endif
 
     if (option->enable_simd && strcmp(comp_ctx->target_arch, "x86_64") != 0
-        && strncmp(comp_ctx->target_arch, "aarch64", 7) != 0) {
+        && strncmp(comp_ctx->target_arch, "aarch64", 7) != 0
+        && strcmp(comp_ctx->target_arch, "arc") != 0) {
         /* Disable simd if it isn't supported by target arch */
         option->enable_simd = false;
     }

core/iwasm/compilation/aot_llvm_extra.cpp

@@ -176,6 +176,9 @@ aot_check_simd_compatibility(const char *arch_c_str, const char *cpu_c_str)
     else if (targetArch == llvm::Triple::aarch64) {
         return subTargetInfo->checkFeatures("+neon");
     }
+    else if (targetArch == llvm::Triple::arc) {
+        return true;
+    }
     else {
         return false;
     }

core/shared/platform/include/platform_api_extension.h

@@ -104,8 +104,9 @@ os_thread_exit(void *retval);
 #endif
 
 /* Clang's __GNUC_PREREQ macro has a different meaning than GCC one,
-   so we have to handle this case specially */
-#if defined(__clang__)
+   so we have to handle this case specially(except the CCAC compiler
+   provided by MetaWare, which doesn't support atomic operations) */
+#if defined(__clang__) && !defined(__CCAC__)
 /* Clang provides stdatomic.h since 3.6.0
    See https://releases.llvm.org/3.6.0/tools/clang/docs/ReleaseNotes.html */
 #if __clang_major__ > 3 || (__clang_major__ == 3 && __clang_minor__ >= 6)