webm2pes/ts: Fix gcc build.

Fix the build and tidy up a couple things along the way.

- Add -std=c++11 to CMakeLists.txt CXX flags.
- Add missing include to libwebm_utils.h (<memory>).
- Setup CMAKE_CXX_FLAGS properly (allow user override).
- Add missing URL for gtest repo to README.libwebm.

BUG=https://bugs.chromium.org/p/webm/issues/detail?id=1136

Change-Id: I894729216737ff92f58a7b7601484ba8fba73b25

CMakeLists.txt

@@ -11,11 +11,14 @@ include("${CMAKE_CURRENT_SOURCE_DIR}/build/msvc_runtime.cmake")
 
 set(LIBWEBM_SRC_DIR "${CMAKE_CURRENT_SOURCE_DIR}")
 
+# Enable C++11 support.
+set(CMAKE_CXX_FLAGS "-std=c++11 ${CMAKE_CXX_FLAGS}" CACHE STRING "" FORCE)
+
 # Turn up the warning levels.
 if(MSVC)
-  set(CMAKE_CXX_FLAGS "/W4 ${CMAKE_CXX_FLAGS}")
+  set(CMAKE_CXX_FLAGS "/W4 ${CMAKE_CXX_FLAGS}" CACHE STRING "" FORCE)
 else ()
-  set(CMAKE_CXX_FLAGS "-Wall -Wextra ${CMAKE_CXX_FLAGS}")
+  set(CMAKE_CXX_FLAGS "-Wall -Wextra ${CMAKE_CXX_FLAGS}" CACHE STRING "" FORCE)
 endif()
 
 # Test configuration flags. Defined here for visibility.

README.libwebm

@@ -77,6 +77,7 @@ build directory:
 
 $ LIBWEBM_TEST_DATA_PATH=path/to/libwebm/testing/testdata ./muxer_tests
 
-Note: Libwebm Googletest integration was built with googletest at git revision
+Note: Libwebm Googletest integration was built with googletest from
+      https://github.com/google/googletest.git at git revision
       ddb8012eb48bc203aa93dcc2b22c1db516302b29.
 

common/libwebm_utils.h

@@ -9,6 +9,7 @@
 #define LIBWEBM_COMMON_LIBWEBM_UTILS_H_
 
 #include <cstdio>
+#include <memory>
 #include <vector>
 
 namespace libwebm {