Changed multi-line C comments into another style.

The left side doesn't look unbalanced.

testcode/lib/atari/defdev.c

@@ -1,8 +1,8 @@
 /*
- * testprogram printing the default device
- *
- * 26-Nov-2009, Christian Groessler
- */
+** testprogram printing the default device
+**
+** 26-Nov-2009, Christian Groessler
+*/
 
 #include <stdio.h>
 #include <conio.h>

testcode/lib/atari/mem.c

@@ -1,8 +1,8 @@
 /*
- * show some memory stuff
- *
- * 04-Aug-2004, Christian Groessler
- */
+** show some memory stuff
+**
+** 04-Aug-2004, Christian Groessler
+*/
 
 #include <stdio.h>
 #include <stdlib.h>

testcode/lib/atari/ostype.c

@@ -1,8 +1,8 @@
 /*
- * testprogram for get_ostype() and get_tv() functions
- *
- * 09-Jul-2004, chris@groessler.org
- */
+** testprogram for get_ostype() and get_tv() functions
+**
+** 09-Jul-2004, chris@groessler.org
+*/
 
 #include <stdio.h>
 #include <atari.h>

testcode/lib/atari/sys.c

@@ -1,10 +1,10 @@
 /*
- * testprogram for _sys() function on Atari
- *
- * 17-Sep-2013, chris@groessler.org
- *
- * uses PUTCHR IOCB function to display a string
- */
+** testprogram for _sys() function on Atari
+**
+** 17-Sep-2013, chris@groessler.org
+**
+** uses PUTCHR IOCB function to display a string
+*/
 
 #include <atari.h>
 #include <6502.h>