nanosvgrast.h: update from mainstream

Fixes invalid memory read on single stop gradient (mainstream PR/252.)
Also removes unnecessary parentheses (mainstream PR/148)
(cherry picked from commit 9fbaa9c)

src/nanosvgrast.h

@@ -357,16 +357,16 @@ static void nsvg__flattenCubicBez(NSVGrasterizer* r,
 
 	dx = x4 - x1;
 	dy = y4 - y1;
-	d2 = nsvg__absf(((x2 - x4) * dy - (y2 - y4) * dx));
-	d3 = nsvg__absf(((x3 - x4) * dy - (y3 - y4) * dx));
+	d2 = nsvg__absf((x2 - x4) * dy - (y2 - y4) * dx);
+	d3 = nsvg__absf((x3 - x4) * dy - (y3 - y4) * dx);
 
 	if ((d2 + d3)*(d2 + d3) < r->tessTol * (dx*dx + dy*dy)) {
 		nsvg__addPathPoint(r, x4, y4, type);
 		return;
 	}
 	++level;
 	if (level > max_level) return;
-	
+
 	x234 = (x23+x34)*0.5f;
 	y234 = (y23+y34)*0.5f;
 	x1234 = (x123+x234)*0.5f;
@@ -1291,8 +1291,9 @@ static void nsvg__initPaint(NSVGcachedPaint* cache, NSVGpaint* paint, float opac
 		for (i = 0; i < 256; i++)
 			cache->colors[i] = 0;
 	} else if (grad->nstops == 1) {
+		unsigned int color = nsvg__applyOpacity(grad->stops[0].color, opacity);
 		for (i = 0; i < 256; i++)
-			cache->colors[i] = nsvg__applyOpacity(grad->stops[i].color, opacity);
+			cache->colors[i] = color;
 	} else {
 		unsigned int ca, cb = 0;
 		float ua, ub, du, u;