json_dumps real value 7.6 as 7.59....96

[mrryanjohnston]

Behavior:

$ gcc main.c -Iinclude -Llib -ljansson -Wl,-rpath,lib
$ ./a.out 
7.5999999999999996
$ ls lib
libjansson.a  libjansson.la  libjansson.so  libjansson.so.4  libjansson.so.4.14.0  pkgconfig
$ ls include/
jansson_config.h  jansson.h
$ cat main.c 
#include <jansson.h>

int main()
{
  json_t *j = json_real(7.6);
  printf("%s\n", json_dumps(j, JSON_ENCODE_ANY));
  return 0;
}
$ ldd ./a.out 
        linux-vdso.so.1 (0x00007ffd2ff7d000)
        libjansson.so.4 => lib/libjansson.so.4 (0x00007f2f8b45b000)
        libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f2f8b220000)
        /lib64/ld-linux-x86-64.so.2 (0x00007f2f8b472000)

Steps to reproduce:

1. download latest release from github: https://github.com/akheron/jansson/releases/tag/v2.14
2. configure with --prefix="/my/current/path"
3. make && make install

I first noticed this with the jansson lib installed in ubuntu via apt, so this should exist in 2.13, as well.