vo_opengl: extend ifdef against shader arrays

GLES2 shaders do not have line continuation characters. Abuse the
HAVE_ARRAYS define to exclude code which uses arrays, and which also
happens to cover all code that defines multi-line macros. (So yes, this
is a hack.)

(cherry picked from commit 2c8d16d89f)

video/out/gl_video_shaders.glsl

@@ -252,7 +252,6 @@ float[6] weights6(sampler2D lookup, float f) {
     vec4 c2 = texture(lookup, vec2(0.75, f));
     return float[6](c1.r, c1.g, c1.b, c2.r, c2.g, c2.b);
 }
-#endif
 
 // For N=n*4 with n>1.
 #define WEIGHTS_N(NAME, N)                          \
@@ -328,6 +327,8 @@ float[6] weights6(sampler2D lookup, float f) {
         return mix(res, clamp(res, lo, hi), ANTIRING);                      \
     }
 
+#endif /* HAVE_ARRAYS */
+
 #ifdef DEF_SCALER0
 DEF_SCALER0
 #endif