Shaders: EXPLICIT_TEXTURE_LAYER is very misleading.

I went through renaming this on many places quite some time ago, but
this one slipped through. Now that UBOs will be a thing, rename to
EXPLICIT_BINDING instead of EXPLICIT_UNIFORM_BINDING.

src/Magnum/Shaders/DistanceFieldVector.frag

@@ -65,7 +65,7 @@ uniform lowp float smoothness
 
 /* Textures */
 
-#ifdef EXPLICIT_TEXTURE_LAYER
+#ifdef EXPLICIT_BINDING
 /* See AbstractVector.h for details about the ID */
 layout(binding = 6)
 #endif

src/Magnum/Shaders/Flat.frag

@@ -66,7 +66,7 @@ uniform highp uint objectId; /* defaults to zero */
 /* Textures */
 
 #ifdef TEXTURED
-#ifdef EXPLICIT_TEXTURE_LAYER
+#ifdef EXPLICIT_BINDING
 layout(binding = 0)
 #endif
 uniform lowp sampler2D textureData;

src/Magnum/Shaders/MeshVisualizer.frag

@@ -113,7 +113,7 @@ uniform lowp vec2 colorMapOffsetScale
 /* Textures */
 
 #if defined(INSTANCED_OBJECT_ID) || defined(VERTEX_ID) || defined(PRIMITIVE_ID) || defined(PRIMITIVE_ID_FROM_VERTEX_ID)
-#ifdef EXPLICIT_TEXTURE_LAYER
+#ifdef EXPLICIT_BINDING
 layout(binding = 4)
 #endif
 uniform lowp sampler2D colorMapTexture;

src/Magnum/Shaders/Phong.frag

@@ -148,7 +148,7 @@ uniform lowp float lightRanges[LIGHT_COUNT]
 /* Textures */
 
 #ifdef AMBIENT_TEXTURE
-#ifdef EXPLICIT_TEXTURE_LAYER
+#ifdef EXPLICIT_BINDING
 layout(binding = 0)
 #endif
 uniform lowp sampler2D ambientTexture;
@@ -156,21 +156,21 @@ uniform lowp sampler2D ambientTexture;
 
 #if LIGHT_COUNT
 #ifdef DIFFUSE_TEXTURE
-#ifdef EXPLICIT_TEXTURE_LAYER
+#ifdef EXPLICIT_BINDING
 layout(binding = 1)
 #endif
 uniform lowp sampler2D diffuseTexture;
 #endif
 
 #ifdef SPECULAR_TEXTURE
-#ifdef EXPLICIT_TEXTURE_LAYER
+#ifdef EXPLICIT_BINDING
 layout(binding = 2)
 #endif
 uniform lowp sampler2D specularTexture;
 #endif
 
 #ifdef NORMAL_TEXTURE
-#ifdef EXPLICIT_TEXTURE_LAYER
+#ifdef EXPLICIT_BINDING
 layout(binding = 3)
 #endif
 uniform lowp sampler2D normalTexture;

src/Magnum/Shaders/Vector.frag

@@ -45,7 +45,7 @@ uniform lowp vec4 color
     #endif
     ;
 
-#ifdef EXPLICIT_TEXTURE_LAYER
+#ifdef EXPLICIT_BINDING
 /* See AbstractVector.h for details about the ID */
 layout(binding = 6)
 #endif

src/Magnum/Shaders/compatibility.glsl

@@ -35,7 +35,7 @@
 #if !defined(GL_ES) && defined(GL_ARB_shading_language_420pack) && !defined(DISABLE_GL_ARB_shading_language_420pack)
     #extension GL_ARB_shading_language_420pack: enable
     #define RUNTIME_CONST
-    #define EXPLICIT_TEXTURE_LAYER
+    #define EXPLICIT_BINDING
 #endif
 
 #if !defined(GL_ES) && defined(GL_ARB_explicit_uniform_location) && !defined(DISABLE_GL_ARB_explicit_uniform_location)
@@ -45,7 +45,7 @@
 
 #if defined(GL_ES) && __VERSION__ >= 300
     #define EXPLICIT_ATTRIB_LOCATION
-    /* EXPLICIT_TEXTURE_LAYER, EXPLICIT_UNIFORM_LOCATION and RUNTIME_CONST is not
+    /* EXPLICIT_BINDING, EXPLICIT_UNIFORM_LOCATION and RUNTIME_CONST is not
        available in OpenGL ES */
 #endif
 

src/Magnum/TextureTools/DistanceFieldShader.frag

@@ -42,7 +42,7 @@ layout(location = 0)
 #endif
 uniform mediump vec2 scaling;
 
-#ifdef EXPLICIT_TEXTURE_LAYER
+#ifdef EXPLICIT_BINDING
 layout(binding = 7)
 #endif
 uniform lowp sampler2D textureData;