Revert "Remove unnecessary hack on Linux by using pthread_mutexattr_settype"

Build error on tinderboxes.

sal/osl/unx/mutex.c

@@ -34,6 +34,12 @@
 #include <pthread.h>
 #include <stdlib.h>
 
+#if defined LINUX /* bad hack */
+int pthread_mutexattr_setkind_np(pthread_mutexattr_t *, int);
+#define pthread_mutexattr_settype pthread_mutexattr_setkind_np
+#define PTHREAD_MUTEX_RECURSIVE PTHREAD_MUTEX_RECURSIVE_NP
+#endif
+
 typedef struct _oslMutexImpl
 {
     pthread_mutex_t mutex;