[BZ #5786]
* elf/dl-sysdep.c: Undefine ROUND after use.
* sysdeps/generic/ldsodefs.h [HAVE_DL_DISCOVER_OSVERSION]
(struct rtld_global_ro): Add _dl_tls_get_addr_soft element.
* elf/rtld.c (rtld_global_ro): Initialize _dl_discover_osversion.
* sysdeps/unix/sysv/linux/dl-osinfo.h: Move _dl_discover_osversion
to ...
* sysdeps/unix/sysv/linux/dl-sysdep.c: ...here.
* sysdeps/unix/sysv/linux/dl-sysdep.h: Declare _dl_discover_osversion
if necessary.
* sysdeps/unix/sysv/linux/sysconf.c: Handle _SC_ARG_MAX here.