improve rules that help incorporate external repos

Rules that help incorporate the [external dbg
repo](https://github.com/lcn2/dbg.git), the [external
dyn_array](https://github.com/lcn2/dyn_array.git), and the [external
jparse repo](https://github.com/lcn2/jparse.git) have been added,
modified or replaced.

For details or to remind yourself of what these rules do, see: `make
dbg.help`, `make dyn_array.help`, `jparse.help`, and `all.help`.

It "goees without saying", so we will say it anyway :-),
some of these rules should be used with case.

.exclude

@@ -1,5 +1,7 @@
 *.a
 *.o
-.?*
+.*.swp
+.DS_Store
 .git
-.gitignore
+.github
+.local.dir.tags