Our <sys/ucred.h> does not provide xucred.

Index: config-scripts/cups-common.m4
--- config-scripts/cups-common.m4.orig
+++ config-scripts/cups-common.m4
@@ -133,7 +133,6 @@ AC_CHECK_HEADER([shadow.h], AC_DEFINE([HAVE_SHADOW_H],
 AC_CHECK_HEADER([stdint.h], AC_DEFINE([HAVE_STDINT_H], [1], [Have <stdint.h> header?]))
 AC_CHECK_HEADER([sys/ioctl.h], AC_DEFINE([HAVE_SYS_IOCTL_H], [1], [Have <sys/ioctl.h> header?]))
 AC_CHECK_HEADER([sys/param.h], AC_DEFINE([HAVE_SYS_PARAM_H], [1], [Have <sys/param.h> header?]))
-AC_CHECK_HEADER([sys/ucred.h], AC_DEFINE([HAVE_SYS_UCRED_H], [1], [Have <sys/ucred.h> header?]))
 
 dnl Checks for iconv.h and iconv_open
 AC_CHECK_HEADER([iconv.h], [