Fix Malloc macro

The last modification made the Malloc return 0

psys/include/p2c/p2c.h

@@ -172,7 +172,7 @@ typedef struct {
 } _TEXT;
 
 /* Memory allocation */
-# define Malloc(n)  (malloc((n != 0) ? (n) : 1) ? 0 : (void*)_OutMem())
+# define Malloc(n)  (malloc((n != 0) ? (n) : 1) ?: (void*)_OutMem())
 #define Free(p)     (free((void*)(p)), (p)=NULL)
 
 /* sign extension */