Use clz to calculate the nearest power of 2

This approach is more efficient, as it removes the loop and uses the
built-in function clz to perform the calculation in constant time.

Author: jserv

src/path.c

@@ -210,9 +210,8 @@ void twin_path_arc(twin_path_t *path,
     if (sides > 1024)
         sides = 1024;
 
-    int32_t n = 2;
-    while ((1 << n) < sides)
-        n++;
+    /* Calculate the nearest power of 2 that is >= sides. */
+    int32_t n = (sides > 1) ? (31 - twin_clz(sides - 1) + 1) : 2;
 
     twin_angle_t step = TWIN_ANGLE_360 >> n;
     twin_angle_t inc = step;