libutil: Clean up more wait cruft from xsys.h
libutil: Clean up more wait cruft from xsys.h

aclements/sv6,aclements/sv6,bowlofstew/sv6,aclements/sv6,bowlofstew/sv6,aclements/sv6,bowlofstew/sv6,aclements/sv6,bowlofstew/sv6,bowlofstew/sv6