Allow use json-c cmake as subproject

Now json-c can be bundled to any cmake-based project and used with
couple lines of code:

add_subdirectory(json-c EXCLUDE_FROM_ALL)
target_link_libraries(MyProject json-c)

Document refcount of json_tokener_parse_ex return

fix c flag loss during cmake building

The real CMake support

Improve pkgconfig setting

This changes allows to use #include <json-c/json.h>
instead of just #include <json.h>

This is normally possible but in some tricky case
this usage is broken without this change.

Here is the case that I encountered. I had to
compile json-c fresh version for some investigations
on newer versions. Then I installed it on my local
environment using option --prefix. After that I
had 2 versions:

 - the system wide version in usual locations
   /usr/lib and /usr/include
 - mine in my HOME directory

Then, as I'm used to include <json-c/json.h>, the
included iheder's version was the system wide one
whereas the linked lib was mine.

Signed-off-by: Jose Bollo <jose.bollo@iot.bzh>

This patch provides a CMakeLists.txt file to build JSON-C library without relying on auto-tools support. This makes the build a bit more portable and cleaner.

It can detect headers and symbols and generate config.h header file based on those detections. It cannot yet handle ctest(1) as the testing itself depends on comparing the output against files. Testing would need some creative abuse of CMake :) This will be provided a few patches later and may possibly involve refactoring test cases.

The patch has been tested on GCC 4.8.5 (Linux), GCC 7.2.0 (MinGW) and Microsoft Visual C++ 16.0 (2010?) locally. Also, compiles correctly on Travis CI and AppVeyor without errors.

cmake: Bump required version

Using 'project(foo VERSION 1.0)' requires CMake 3.0, the VERSION option
is not part of CMake 2.8.7, see:

* https://cmake.org/cmake/help/v2.8.7/cmake.html#command:project
* https://cmake.org/cmake/help/v3.0/release/3.0.0.html#commands

The property C_STANDARD was introduced with CMake 3.1, see:

* https://cmake.org/cmake/help/v3.1/release/3.1.0.html#properties

Signed-off-by: Alexander Dahl <post@lespocky.de>

Resolve windows name conflict

install json_object_iterator.h header file

When building the project using cmake then installing it.  The
definitions in `json_object_iterator.h` are required but not installed
by the cmake install rule.  This patch adds the `json_object_iterator.h`
file to the list of files to install.

Signed-off-by: Keith Holman <keith.holman@windriver.com>

arraylist: Fixed names of parameters for callback function

1. The windows dll will output the lib and dll, and rename the static
    lib will have conflict on windows.
2. Delete rename code to dismiss the conflict.

Fixed typos

Add fuzzers from OSS-Fuzz

Avoid uninitialized variable warnings

Fix json_object_object_foreach to avoid uninitialized variable warnings
using ANSI C or MSC.

Also try to accomodate formats to explicitly exclude the decimal (e.g. %.0f).

json_object_private: Use unsigned 32-bit integer type for refcount

json_object: Avoid double free (and thus a segfault) when ref_count gets < 0

Makefile: Add ACLOCAL_AMFLAGS

Fix non-GNUC define for JSON_C_CONST_FUNCTION

This is recommended by the libtool manual.