fix typo in debug code

Fonderie/sfx.c

@@ -425,8 +425,9 @@ int des_bords_sombres_b(FloatImg *pimg, int nbre)
 {
 int		idx, x, foo;
 float		coef, *fptr;
+
 #if DEBUG_LEVEL
-fprintf(stderr, ">>> %s ( %p %d )\n", __func__, pimg, offset);
+fprintf(stderr, ">>> %s ( %p %d )\n", __func__, pimg, nbre);
 #endif
 
 for (idx=0; idx<nbre; idx++) {