Structs starting with 'u' in sys

• ufs_args sys/mount.h:206
• ufs_specific sys/namei.h:77
• uio sys/uio.h:56
• unpcb sys/unpcb.h:62
• uprof sys/resourcevar.h:53
• user sys/user.h:59
• utsname sys/utsname.h:42