+SYSTEM:=$(shell uname)
+
+ifeq ($(SYSTEM),Linux)
+ ifneq ($(shell expr "`cat /etc/issue`" : '.*Debian.*'),0)
+ # Old Debian used /usr/share/sgml/docbook, new Debian uses
+ # /usr/share/xml/docbook.
+ ifneq ($(shell expr "`ls -d /usr/share/xml`" : '.*/usr/share/xml.*'),0)
+ OS:=debian
+ else
+ # Evidently it's not a new-style Debian DocBook setup, ergo:
+ OS:=debian-old
+ endif
+ else
+ ifneq ($(shell expr "`cat /etc/issue`" : '.*SuSE.*'),0)
+ OS=suse
+ else
+ ifneq ($(shell expr "`cat /etc/issue`" : 'Red Hat Linux release 9'),0)
+ OS=redhat9
+ else
+ ifneq ($(shell expr "`cat /etc/issue`" : '.*Yarrow.*'),0)
+ OS=fedora1
+ endif
+ endif