This is an ABI breaking change, but
typedef int greg_t;
is not a useful definition on aarch64.
greg_t is usually used for defining gregset_t which is used
in mcontext_t. The general registers in mcontext_t can only
be accessed by target specific code and on aarch64 greg_t
is not needed for that so this change is not supposed to break
existing code, just fix the definition.
[BZ #18648]
* sysdeps/unix/sysv/linux/aarch64/sys/ucontext.h (greg_t): Change the
definition to elf_greg_t.
(Added another BZ entry that was missed in the previous commit).