#define XST_mUV(i,v) (ST(i) = sv_2mortal(newSVuv(v)) )
#define XST_mNV(i,v) (ST(i) = sv_2mortal(newSVnv(v)) )
#define XST_mPV(i,v) (ST(i) = sv_2mortal(newSVpv(v,0)))
-#define XST_mPVN(i,v,n) (ST(i) = sv_2mortal(newSVpvn(v,n)))
+#define XST_mPVN(i,v,n) (ST(i) = newSVpvn_flags(v,n, SVs_TEMP))
#define XST_mNO(i) (ST(i) = &PL_sv_no )
#define XST_mYES(i) (ST(i) = &PL_sv_yes )
#define XST_mUNDEF(i) (ST(i) = &PL_sv_undef)