Segfault when linking with mxml library

[duttajnu]

In last release v3.3, initialization of global data removed from '_MXML_FINI' which is registered as destructor for GNUC,

#elif defined(__GNUC__) /* Linux and Mac OS X */
#  define _MXML_FINI __attribute((destructor)) _mxml_fini
#else

which try to delete the pthread key,

 static void
 _MXML_FINI(void)
 {
   pthread_key_delete(_mxml_key);
 }

This causes segfault on the application which exits/terminates before calling any mxml api.

The above mentioned change has been introduced with below commit: 02f3310322e9d6613d17354fa98b297411d6ccf3

[michaelrsweet]

Sigh...

[michaelrsweet]

Treating this as a dupe of #293.