Fix #32: va_arg for generic data types

Author: DreamPearl

src/usr/include/stdarg.h

@@ -6,12 +6,12 @@ namespace std {
 #endif
 
 typedef struct va_list {
-    int *base;  // using int* to jmp at 4 bytes gap
+    void *base;
 } va_list;
 
-#define va_start(list, last) ((list).base = (((int*)&(last))+1))
+#define va_start(list, last) ((list).base = (((void*)&(last))+1))
 #define va_end(list) (list).base = NULL
-#define va_arg(list, type) (*(type*)((list).base++))
+#define va_arg(list, type) (*(type*)((list).base+=sizeof(type)))
 #define va_copy(dst, src) (dst).base = (src).base
 
 #ifdef __cplusplus