-DEBIAN=expr "`cat /etc/issue`" : '.*Debian.*'
-SUSE=expr "`cat /etc/issue`" : '.*SuSE.*'
-REDHAT=expr "`cat /etc/issue`" : '.*RedHat.*'
+DEBIAN=$(shell expr "`cat /etc/issue`" : '.*Debian.*')
+SUSE=$(shell expr "`cat /etc/issue`" : '.*SuSE.*')
+SUSE91=$(shell expr "`cat /etc/issue`" : '.*SuSE Linux 9.1.*')
+REDHAT=$(shell expr "`cat /etc/issue`" : '.*RedHat.*')