Make alt code variables in Makefiles consistent

That is the comments have a general form and if they're for the alt code
they're defined in the alt code section. If they're for the entry and
the alt code they're above the CDEFINE variable.

The thanks file has been updated where it was needed.

Now only entries that have not been done need this improvement.

2000/thadgavin/Makefile

@@ -56,7 +56,7 @@ CSTD= -std=gnu99
 #
 ARCH=
 
-# variables for redefining the time to sleep, primarily for alt code
+# Variable to control amount of time to sleep between updates for alt code.
 #
 SLEEP= 30
 SDL_SLEEP= 150000