Replaced whole bunch for Makefiles with a single generic Makefile.

- No complex shell logic.
- "Source file shadowing" for all targets via vpath.
- Dependency handling.
- True incremental build.
- Don't write into source directories.
- Easy cleanup by just removing 'wrk'.

libsrc/apple2/mouse_stat_stddrv.s

@@ -7,8 +7,16 @@
 ;
 
         .export	_mouse_static_stddrv
-        .import	_apple2_stdmou
+        .ifdef	__APPLE2ENH__
+        .import	_a2e_stdmou_mou
+        .else
+        .import	_a2_stdmou_mou
+        .endif
 
 .rodata
 
-_mouse_static_stddrv := _apple2_stdmou
+        .ifdef	__APPLE2ENH__
+_mouse_static_stddrv := _a2e_stdmou_mou
+        .else
+_mouse_static_stddrv := _a2_stdmou_mou
+        .endif