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/FindUVWASI.cmake

@@ -0,0 +1,25 @@
+# Copyright (C) 2023 Intel Corporation.  All rights reserved.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+# Find libuvwasi library
+# This module defines
+#  UVWASI_FOUND, if false, do not try to link to libuvwasi
+#  UVWASI_LIBRARIES
+#  UVWASI_INCLUDE_DIR, where to find headers
+
+find_path(UVWASI_INCLUDE_DIR NAMES uvwasi.h wasi_serdes.h wasi_types.h PATH_SUFFIXES uvwasi)
+find_library(UVWASI_LIBRARIES NAMES uvwasi_a)
+
+include(FindPackageHandleStandardArgs)
+
+find_package_handle_standard_args(
+  UVWASI
+  FOUND_VAR UVWASI_FOUND
+  REQUIRED_VARS
+    UVWASI_LIBRARIES
+    UVWASI_INCLUDE_DIR
+)
+
+if(UVWASI_FOUND)
+  set(UVWASI_INCLUDE_DIR ${UVWASI_INCLUDE_DIR}/uvwasi)
+endif()