ext: add LC3 codec library

Adds LC3 codec implementation from https://github.com/google/liblc3

ext/liblc3/pkg.yml

@@ -0,0 +1,50 @@
+#
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#  http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+#
+
+pkg.name: ext/liblc3
+pkg.description: LC3 Codec library
+pkg.author: "Apache Mynewt <[email protected]>"
+pkg.homepage: "http://mynewt.apache.org/"
+pkg.keywords:
+    - lc3
+
+pkg.type: sdk
+
+pkg.cflags: -O3 -std=c11 -ffast-math -Wno-array-bounds
+pkg.lflags: -lm
+
+pkg.ign_dirs:
+    - "@liblc3/test"
+    - "@liblc3/zephyr"
+    - "@liblc3/fuzz"
+    - "@liblc3/tables"
+    - "@liblc3/tools"
+
+pkg.src_dirs:
+    - "@liblc3/src"
+
+pkg.include_dirs:
+    - "@liblc3/include"
+
+repository.liblc3:
+    type: github
+    vers: v1.0.4-commit
+    branch: main
+    user: google
+    repo: liblc3