As per discussion in - https://github.com/open-source-parsers/jsoncpp/issues/404
Null should not be pass to memcmp, it may show undesired behaviour, so avoid doing that using assertion.
Also, changed one direct "assert" to JSON_ASSERT - it will be decided if exceptions are used or not.
See https://github.com/open-source-parsers/jsoncpp/issues/411#issuecomment-180974558
I was unable to produce a warning in Clang, so I am not certain. But based on a [SO answer](http://stackoverflow.com/questions/25480059/gcc-conversion-warning-when-assigning-to-a-bitfield), I think I've fixed the following:
```
/tmp/jsoncpp/src/lib_json/json_value.cpp: In copy constructor 'Json::Value::CZString::CZString(const Json::Value::CZString&)':
/tmp/jsoncpp/src/lib_json/json_value.cpp:235:18: error: conversion to 'unsigned char:2' from 'unsigned int' may alter its value [-Werror=conversion]
storage_.policy_ = (other.cstr_
~~~~~~~~~~~~
? (static_cast<DuplicationPolicy>(other.storage_.policy_) == noDuplication
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
? noDuplication : duplicate)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
: static_cast<DuplicationPolicy>(other.storage_.policy_));
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
```
- if building as a submodule of another repository, installation of pkg-config files can fail because they may not be in the top-level binary directory
- changing ${CMAKE_BINARY_DIR} to ${CMAKE_CURRENT_BINARY_DIR} allow CMake to find the files for installation
'-pedantic' issues all warnings demanded by strict ISO C/C++; rejecting
extensions that do not follow ISO C/C++. Without this option, certain GNU
extensions and traditional C/C++ features are supported as well.
With this option enabled building jsoncpp fails with the musl toolchain on
x86 because of an incompatible posix_memalign declaration [1]. Without
'-pedantic' there is no error anymore and jsoncpp builds fine.
Add an option JSONCPP_WITH_STRICT_ISO to disable compilation with '-pedantic'
with GCC. If jsoncpp is build with the JSONCPP_WITH_WARNING_AS_ERROR option
'-pedantic-errors' is used instead.
[1] https://gcc.gnu.org/ml/gcc-patches/2015-05/msg01425.html
* Add move constructor to Value::CZString
* Add unit test for Value move constructor
* Allow includer to specify in advance the value for
JSON_HAS_RVALUE_REFERENCES
