CMake: Option was not enabled by default as intended.
Makefile: Flags were not passed when building the tests

This is not changing the behavior of the code, but it is improving the
readability and helps to make the intention clearer.

One thing to take care: 'true' should never be compared against.

When comparing the type, it has to be masked with 0xFF because of
cJSON_IsConst and cJSON_IsReference.

Release version 1.0.0

And remove special handling of SunOs

This can be disabled when the exporting of the targets causes problems.

This is for compatibility reasons with old CMake 2.8 versions.

The prior approach was exporting paths from the build environment.

Fix library and include paths in pkg-config, CMakeLists.txt and the
CMake config files.

These files will allow cmake based projects to find the
library using find_package(cJSON). If successful, they can
use CJSON_LIBRARIES and CJSON_INCLUDE_DIRS.

Other build systems can use a similar approach to pkg-config:
cmake --find-package -DNAME=cJSON -DCOMPILER_ID=GNU -DLANGUAGE=C  -DCMAKE_PREFIX_PATH=<path-to-non-sytem-installation-path> -DMODE=LINK

or with MODE COMPILE or EXISTS.

Turned off by default.