remove unused variable

Author: recp

include/cglm/affine-mat.h

@@ -110,8 +110,7 @@ glm_mul_rot(mat4 m1, mat4 m2, mat4 dest) {
 
         b00 = m2[0][0], b01 = m2[0][1], b02 = m2[0][2],
         b10 = m2[1][0], b11 = m2[1][1], b12 = m2[1][2],
-        b20 = m2[2][0], b21 = m2[2][1], b22 = m2[2][2],
-        b33 = m2[3][3];
+        b20 = m2[2][0], b21 = m2[2][1], b22 = m2[2][2];
 
   dest[0][0] = a00 * b00 + a10 * b01 + a20 * b02;
   dest[0][1] = a01 * b00 + a11 * b01 + a21 * b02;