Use system libuv if available (#1861)

This PR attempts to search for the system libuv and use it if found instead of
downloading it. As reported in #1831, this is needed because some tools
build in a sandbox and clear the extra sources.

core/iwasm/libraries/libc-uvwasi/FindLIBUV.cmake

@@ -0,0 +1,28 @@
+# Copyright (C) 2023 Intel Corporation.  All rights reserved.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+# Find libuv library
+# This module defines
+#  LIBUV_FOUND, if false, do not try to link to libuv
+#  LIBUV_LIBRARIES
+#  LIBUV_INCLUDE_DIR, where to find uv.h
+
+find_path(LIBUV_INCLUDE_DIR NAMES uv.h)
+find_library(LIBUV_LIBRARIES NAMES uv libuv)
+
+include(FindPackageHandleStandardArgs)
+
+find_package_handle_standard_args(
+  LIBUV
+  FOUND_VAR LIBUV_FOUND
+  REQUIRED_VARS
+    LIBUV_LIBRARIES
+    LIBUV_INCLUDE_DIR
+)
+
+if(WIN32)
+  list(APPEND LIBUV_LIBRARIES iphlpapi)
+  list(APPEND LIBUV_LIBRARIES psapi)
+  list(APPEND LIBUV_LIBRARIES userenv)
+  list(APPEND LIBUV_LIBRARIES ws2_32)
+endif()