Have a more compatible Makefile ?

Have a more compatible Makefile ?

The patsubst function introduced in sarg 2.3 to avoid the duplicate
file name lists in Makefile.in is a GNU make extension that is not
supported by BSD make. Therefore sarg 2.3 fails to compile on that
system with the default make command.

According to the GNU make documentation, the variable substitution
should be more compatible with other implementations but it isn't
clear whether it is accepted by BSD make or not. Let's try it.