The ifunc handling for strcspn is adjusted in order to omit ifunc
variants if those will never be used as the minimum architecture level
already supports newer CPUs by default.
Glibc internal calls will then also use the "newer" ifunc variant.
ChangeLog:
* sysdeps/s390/multiarch/Makefile
(sysdep_routines): Remove strcspn variants.
* sysdeps/s390/Makefile (sysdep_routines): Add strcspn variants.
* sysdeps/s390/multiarch/ifunc-impl-list.c
(__libc_ifunc_impl_list): Refactor ifunc handling for strcspn.
* sysdeps/s390/multiarch/strcspn-c.c: Move to ...
* sysdeps/s390/strcspn-c.c: ... here and adjust ifunc handling.
* sysdeps/s390/multiarch/strcspn-vx.S: Move to ...
* sysdeps/s390/strcspn-vx.S: ... here and adjust ifunc handling.
* sysdeps/s390/multiarch/strcspn.c: Move to ...
* sysdeps/s390/strcspn.c: ... here and adjust ifunc handling.
* sysdeps/s390/ifunc-strcspn.h: New file.
