Update upstream version of jsoncpp and run tests

ports/jsoncpp/nacl.patch

+diff --git a/CMakeLists.txt b/CMakeLists.txt
+index 462f278..c1a6712 100644
+--- a/CMakeLists.txt
++++ b/CMakeLists.txt
+@@ -94,10 +94,10 @@ endif( MSVC )
+ 
+ if (CMAKE_CXX_COMPILER_ID MATCHES "Clang")
+   # using regular Clang or AppleClang
+-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11 -Wall")
++  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=gnu++11 -Wall")

[binji, 2015/04/02 07:39:07]

TODO here? We could remove this when we kill the GCC toolchains

[Sam Clegg, 2015/04/02 17:58:48]

Done.

+ elseif ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU")
+   # using GCC
+-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++0x -Wall -Wextra -pedantic")
++  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=gnu++0x -Wall -Wextra -pedantic")
+ endif()
+ 
+ IF(JSONCPP_WITH_WARNING_AS_ERROR)
+diff --git a/src/lib_json/json_writer.cpp b/src/lib_json/json_writer.cpp
+index ef976bf..f7ad1e2 100644
+--- a/src/lib_json/json_writer.cpp
++++ b/src/lib_json/json_writer.cpp
+@@ -29,8 +29,6 @@
+ 
+ #if defined(_MSC_VER) && _MSC_VER < 1500 // VC++ 8.0 and below
+ #define snprintf _snprintf
+-#elif __cplusplus >= 201103L
+-#define snprintf std::snprintf
+ #endif
+ 
+ #if defined(_MSC_VER) && _MSC_VER >= 1400 // VC++ 8.0
+diff --git a/src/test_lib_json/main.cpp b/src/test_lib_json/main.cpp
+index 71e9491..6bd1778 100644
+--- a/src/test_lib_json/main.cpp
++++ b/src/test_lib_json/main.cpp
+@@ -679,7 +679,9 @@ JSONTEST_FIXTURE(ValueTest, integers) {
+   JSONTEST_ASSERT_EQUAL(kint32max, val.asUInt());
+   JSONTEST_ASSERT_EQUAL(kint32max, val.asLargestUInt());
+   JSONTEST_ASSERT_EQUAL(kint32max, val.asDouble());
++#if !(defined(__native_client__) && defined(__i386__))

[binji, 2015/04/02 07:39:07]

Add TODO explaining this test failure?

[Sam Clegg, 2015/04/02 17:58:48]

Done.

+   JSONTEST_ASSERT_EQUAL(kfint32max, val.asFloat());
++#endif
+   JSONTEST_ASSERT_EQUAL(true, val.asBool());
+   JSONTEST_ASSERT_STRING_EQUAL("2147483647", val.asString());
+