The json-c library is used in cryptsetup for LUKS2 header information.
Since cryptsetup can be called very early during boot, the developers
avoid getrandom() calls in their own code base for now. [1]

Introducing a blocking getrandom() call in json-c therefore introduces
this issue for cryptsetup as well. Even though cryptsetup issues do not
have to be json-c issues, here is my proposal:

Let's use a non-blocking call, falling back to other sources if the call
would block. Since getrandom() accesses urandom, it must mean that we
are in an early boot phase -- otherwise the call would not block
according to its manual page.

As stated in manual page of random(4), accessing /dev/urandom won't
block but return weak random numbers, therefore this fallback would work
for json-c.

While at it, fixed the debug message.

[1] https://gitlab.com/cryptsetup/cryptsetup/-/merge_requests/47
    which references to https://lwn.net/Articles/800509/

Lower overhead than opening & reading from /dev/urandom, and works
in chroots and other situtations where /dev/urandom is not available.
Falls back to existing methods when kernel doesn't support the syscall.

Example:
mkdir build && cd build
cmake -DOVERRIDE_GET_RANDOM_SEED='do { extern uint32_t getMsTicks(void); int ms = getMsTicks() * 433494437; return ms; } while(0)' ..

Some CPUs advertise RDRAND in CPUID, but return 0xFFFFFFFF
unconditionally. To avoid locking up later, test RDRAND during
initialization, and if it returns 0xFFFFFFFF, mark it as nonexistent.

Fixes #588.

2.replace json_object_get/put API with json_object_retain/release, as they operate the reference counter, and confused with array_list_get/put_idx.
3.replace array_list_get/put_idx API with array_list_get/insert to make them more clear to use.

If we want to override `strerror()` in libjson-c
to make tests consistent across platforms, we
need to do it build-wide as configure/build
option.

Apple linkers make it really hard to override functions
at link-time, and this seems to be locked down on travis-ci.org
[ for security reasons I assume ].
While I got it to work locally, it did not work
when running on travis.

Signed-off-by: Alexandru Ardelean <ardeleanalex@gmail.com>

Remove trailing whitespaces

Fix build using MinGW.

MinGW requires wincrypt.h.
GCC does not support #pragma comment, which trips Werror.

* CVE-2013-6371: hash collision denial of service
* CVE-2013-6370: buffer overflow if size_t is larger than int