The dl-procinfo.h for linux/s390 and linux/i386 don't have include
guards, which causes them to fail since addition of LD_HWCAP_MASK to
tunables. Add _DL_I386_PROCINFO_H guard to avoid redefining
_dl_procinfo on multiple includes and also allow the subsequent
include of another dl-procinfo.h to work.
Verified with a build test on i686.
* sysdeps/unix/sysv/linux/i386/dl-procinfo.h: Add include
guard.
* sysdeps/unix/sysv/linux/s390/dl-procinfo.h: Likewise.