If dst->virgin is set, dst->x, y, w and h are uninitialised. The result
of the addition is already not used, but the addition itself can trigger
floating point exceptions, so make sure it's not performed.

--- librsvg-2.16.1/rsvg-base.c
+++ librsvg-2.16.1/rsvg-base.c
@@ -1678,12 +1678,17 @@
 void rsvg_bbox_insert(RsvgBbox * dst, RsvgBbox * src)
 {
 	double affine[6];
-	double xmin = dst->x, ymin = dst->y;
-	double xmax = dst->x + dst->w, ymax = dst->y + dst->h;
+	double xmin, ymin;
+	double xmax, ymax;
 	int i;
 
 	if (src->virgin)
 		return;
+	if (!dst->virgin)
+		{
+			xmin = dst->x, ymin = dst->y;
+			xmax = dst->x + dst->w, ymax = dst->y + dst->h;
+		}
 	_rsvg_affine_invert(affine, dst->affine);
 	_rsvg_affine_multiply(affine, src->affine, affine);