This patch uses the libc_ifunc macro to create already existing ifunc functions
longjmp_ifunc, siglongjmp_ifunc if HAVE_IFUNC is defined.
The s390 pt-longjmp.c includes the common pt-longjmp.c and uses strong_alias
to create the longjmp, siglongjmp symbols for glibc version 2.19.
ChangeLog:
* nptl/pt-longjmp.c (DEFINE_LONGJMP): Use libc_ifunc macro.
* sysdeps/unix/sysv/linux/s390/pt-longjmp.c (longjmp, siglongjmp):
Use strong_alias to create symbols for glibc verison 2.19.