Validate the build type argument value in function build_webrtc

webrtc/build/ios/build_ios_libs.sh

 #!/bin/bash
 
 #  Copyright 2015 The WebRTC project authors. All Rights Reserved.
 #
 #  Use of this source code is governed by a BSD-style license
 #  that can be found in the LICENSE file in the root of the source
 #  tree. An additional intellectual property rights grant can be found
 #  in the file PATENTS.  All contributing project authors may
 #  be found in the AUTHORS file in the root of the source tree.
 
@@ skipping 55 matching lines @@
   if [[ -n "${custom_gn_options}" ]]; then
     GN_ARGS="${GN_ARGS} ${custom_gn_options}"
   fi
 
   # Generate static or dynamic.
   if [[ ${build_type} = "static_only" ]]; then
     GN_TARGET_NAME="rtc_sdk_objc"
   elif [[ ${build_type} == "framework" ]]; then
     GN_TARGET_NAME="rtc_sdk_framework_objc"
     GN_ARGS="${GN_ARGS} enable_dsyms=true enable_stripping=true"
+  else
+    echo "Build type \"${build_type}\" is not supported."
+    exit 1
   fi
 
   echo "Building WebRTC with args: ${GN_ARGS}"
   gn gen ${OUTPUT_DIR} --args="${GN_ARGS}"
   echo "Building target: ${GN_TARGET_NAME}"
   ninja -C ${OUTPUT_DIR} ${GN_TARGET_NAME}
 
   # Strip debug symbols to reduce size.
   if [[ ${build_type} = "static_only" ]]; then
     strip -S ${OUTPUT_DIR}/obj/webrtc/sdk/lib${GN_TARGET_NAME}.a -o \
@@ skipping 118 matching lines @@
   VERSION_NUMBER="${MAJOR_MINOR}.${WEBRTC_REVISION}"
   echo "Substituting revision number: ${VERSION_NUMBER}"
   PlistBuddy -c "Set :CFBundleVersion ${VERSION_NUMBER}" ${INFOPLIST_PATH}
   plutil -convert binary1 ${INFOPLIST_PATH}
 else
   echo "BUILD_TYPE ${BUILD_TYPE} not supported."
   exit 1
 fi
 
 echo "Done."