-$(PERL_INSTALLERS) = $(addprefix install.perl.,$(PERL_PROGS))
-$(BASH_INSTALLERS) = $(addprefix install.bash.,$(BASH_PROGS))
+else
+
+PERL_PROGS =
+BASH_PROGS =
+
+endif
+
+PERL_INSTALLERS = $(addprefix install.perl.,$(PERL_PROGS))
+BASH_INSTALLERS = $(addprefix install.bash.,$(BASH_PROGS))