Create a placeholder for WASI threads implementation (#1783)

This a simpler version of the PR: https://github.com/bytecodealliance/wasm-micro-runtime/pull/1638

samples/wasi-threads/wasm-apps/CMakeLists.txt

@@ -0,0 +1,29 @@
+# Copyright (C) 2022 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+if (NOT DEFINED WASI_SDK_DIR)
+  set (WASI_SDK_DIR               "/opt/wasi-sdk")
+endif ()
+
+set (CMAKE_SYSROOT                  "${WASI_SYSROOT}")
+set (CMAKE_C_COMPILER               "${WASI_SDK_DIR}/bin/clang")
+set (CMAKE_C_COMPILER_TARGET        "wasm32-wasi")
+
+function (compile_sample SOURCE_FILE)
+  get_filename_component (FILE_NAME ${SOURCE_FILE} NAME_WLE)
+  set (WASM_MODULE ${FILE_NAME}.wasm)
+  add_executable (${WASM_MODULE} ${SOURCE_FILE})
+
+  target_compile_options (${WASM_MODULE} PRIVATE
+    -pthread -ftls-model=local-exec)
+
+  target_link_options (${WASM_MODULE} PRIVATE
+    -z stack-size=32768
+    LINKER:--export=__heap_base
+    LINKER:--export=__data_end
+    LINKER:--shared-memory,--max-memory=1966080
+    LINKER:--export=wasi_thread_start
+  )
+endfunction ()
+
+compile_sample(no_pthread.c)