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/atari/joy_stat_stddrv.s

@@ -7,8 +7,8 @@
 ;
 
         .export	_joy_static_stddrv
-        .import	_atari_stdjoy
+        .import	_ataristd_joy
 
 .rodata
 
-_joy_static_stddrv := _atari_stdjoy
+_joy_static_stddrv := _ataristd_joy

libsrc/atari/tgi_stat_stddrv.s

@@ -7,8 +7,8 @@
 ;
 
         .export	_tgi_static_stddrv
-        .import	_atari_8
+        .import	_atari8_tgi
 
 .rodata
 
-_tgi_static_stddrv := _atari_8
+_tgi_static_stddrv := _atari8_tgi