Moved selection of I915 hack out of the YUV shader.

client/deps/glbench/src/yuv2rgb_2.glslf

Index: client/deps/glbench/src/yuv2rgb_2.glslf
diff --git a/client/deps/glbench/src/yuv2rgb_2.glslf b/client/deps/glbench/src/yuv2rgb_2.glslf
index 8f2276314b9bcea812af0d0a5144b81463b08986..81c7a17a662177b6d978707b9b1e2f6e7cc60345 100644
--- a/client/deps/glbench/src/yuv2rgb_2.glslf
+++ b/client/deps/glbench/src/yuv2rgb_2.glslf
@@ -35,8 +35,6 @@
  * of the original image is 2 modulo 4.
  */
 
-#define I915_WORKAROUND 1
-
 uniform sampler2D textureSampler;
 uniform sampler2D paritySampler;
 
@@ -49,7 +47,7 @@ void main() {
   /*
    * If the height of the original image is even, offset_odd is not needed.
    */
-#if I915_WORKAROUND
+#if defined(I915_WORKAROUND)
   vec2 offset_even = vec2(texture2D(paritySampler, gl_TexCoord[0].xy).x * 0.5,
                           0.0);
 #else
@@ -57,7 +55,7 @@ void main() {
 #endif
   vec2 offset_odd = vec2(0.5 - offset_even.x, 0.0);
 
-#if I915_WORKAROUND
+#if defined(I915_WORKAROUND)
   float yChannel = texture2D(textureSampler, gl_TexCoord[0].zw).x;
   float uChannel = texture2D(textureSampler, gl_TexCoord[1].xy + offset_even).x;
   float vChannel = texture2D(textureSampler, gl_TexCoord[1].zw + offset_odd).x;