The new configure/install system wasn't working for Oracle Linux v6.

build-aux/ax_nagios_get_distrib

@@ -110,6 +110,8 @@ AC_DEFUN([AX_NAGIOS_GET_DISTRIB_TYPE],
 					. /etc/os-release
 					if test x"$ID_LIKE" != x; then
 						dist_type=`echo $ID_LIKE | cut -d' ' -f1 | tr ["[A-Z]" "[a-z]"]`
+					elif test x"$ID" = xol; then
+						dist_type=rh
 					else
 						dist_type=`echo $ID | tr ["[A-Z]" "[a-z]"]`
 					fi

configure

@@ -2794,6 +2794,8 @@ esac
 					. /etc/os-release
 					if test x"$ID_LIKE" != x; then
 						dist_type=`echo $ID_LIKE | cut -d' ' -f1 | tr "[A-Z]" "[a-z]"`
+					elif test x"$ID" = xol; then
+						dist_type=rh
 					else
 						dist_type=`echo $ID | tr "[A-Z]" "[a-z]"`
 					fi