Added special strdup to liboptions, to prevent memory leaks for option strings

If you are doing memory leak debugging you don't want to see any leaks when
stopping the program.

src/libdebug/debug.c

@@ -28,6 +28,7 @@
 #include "../libsample/sample.h"
 #include "debug.h"
 #include "../libdisplay/display.h"
+#include "../liboptions/options.h"
 
 const char *debug_level[] = {
 	"debug  ",
@@ -206,7 +207,7 @@ int parse_debug_opt(const char *optarg)
 	for (i = 0; debug_level[i]; i++)
 		max_level = i;
 	
-	dstring = strdup(optarg);
+	dstring = options_strdup(optarg);
 	p = strsep(&dstring, ",");
 	for (i = 0; i < p[i]; i++) {
 		if (p[i] < '0' || p[i] > '9') {