Fix -Wextra warning in stb_truetype.h

stb_truetype.h

@@ -1745,7 +1745,7 @@ static void stbtt__fill_active_edges(unsigned char *scanline, int len, stbtt__ac
 
 static void stbtt__rasterize_sorted_edges(stbtt__bitmap *result, stbtt__edge *e, int n, int vsubsample, int off_x, int off_y, void *userdata)
 {
-   stbtt__hheap hh = { 0 };
+   stbtt__hheap hh = { 0, 0, 0 };
    stbtt__active_edge *active = NULL;
    int y,j=0;
    int max_weight = (255 / vsubsample);  // weight per vertical scanline
@@ -2047,7 +2047,7 @@ static void stbtt__fill_active_edges_new(float *scanline, float *scanline_fill,
 // directly AA rasterize edges w/o supersampling
 static void stbtt__rasterize_sorted_edges(stbtt__bitmap *result, stbtt__edge *e, int n, int vsubsample, int off_x, int off_y, void *userdata)
 {
-   stbtt__hheap hh = { 0 };
+   stbtt__hheap hh = { 0, 0, 0 };
    stbtt__active_edge *active = NULL;
    int y,j=0, i;
    float scanline_data[129], *scanline, *scanline2;