-#define isWARN_on(c,x) (IsSet(SvPVX_const(c), 2*(x)))
-#define isWARNf_on(c,x) (IsSet(SvPVX_const(c), 2*(x)+1))
+#define isWARN_on(c,x) (IsSet((U8 *)(c + 1), 2*(x)))
+#define isWARNf_on(c,x) (IsSet((U8 *)(c + 1), 2*(x)+1))
+
+#define DUP_WARNINGS(p) \
+ (specialWARN(p) ? (STRLEN*)(p) \
+ : (STRLEN*)CopyD(p, PerlMemShared_malloc(sizeof(*p)+*p), sizeof(*p)+*p, \
+ char))