* sysdeps/unix/sysv/linux/ia64/clone2.S: Check for NULL stakc
pointers to match other architectures.
* sysdeps/unix/sysv/linux/Makefile [subdirs=misc] (tests): Add
tst-clone.
* sysdeps/unix/sysv/linux/tst-clone.c: New file.
malloc'ed wbuffer which isn't freed in error conditions.