Increase the maximum reserved VT number to 32

The display switch features depend on each session having a VT number, thus it is important to have a suffucient number of VTs available for use
Most Linux distributions allow 64 VTs by default, and the kernel allows up to 256 VTs

tdm/backend/dm.c

@@ -51,7 +51,7 @@ from the copyright holder.
 # include <sys/vt.h>
 #endif
 
-#define MAX_VT_NUMBER 16
+#define MAX_VT_NUMBER 32
 
 static void SigHandler( int n );
 static int ScanConfigs( int force );