Default shader attrib locations need to be exposed

They need to be exposed on `rlgl.h` header section (not implementation section) because with some specific use cases (custom config.h, rmodels module enabled), building fails otherwise.

src/rlgl.h

@@ -322,6 +322,26 @@
 #define RL_READ_FRAMEBUFFER                     0x8CA8      // GL_READ_FRAMEBUFFER
 #define RL_DRAW_FRAMEBUFFER                     0x8CA9      // GL_DRAW_FRAMEBUFFER
 
+// Default shader vertex attribute locations
+#ifndef RL_DEFAULT_SHADER_ATTRIB_LOCATION_POSITION
+    #define RL_DEFAULT_SHADER_ATTRIB_LOCATION_POSITION  0
+#endif
+#ifndef RL_DEFAULT_SHADER_ATTRIB_LOCATION_TEXCOORD
+    #define RL_DEFAULT_SHADER_ATTRIB_LOCATION_TEXCOORD  1
+#endif
+#ifndef RL_DEFAULT_SHADER_ATTRIB_LOCATION_NORMAL
+    #define RL_DEFAULT_SHADER_ATTRIB_LOCATION_NORMAL    2
+#endif
+#ifndef RL_DEFAULT_SHADER_ATTRIB_LOCATION_COLOR
+    #define RL_DEFAULT_SHADER_ATTRIB_LOCATION_COLOR     3
+#endif
+    #ifndef RL_DEFAULT_SHADER_ATTRIB_LOCATION_TANGENT
+#define RL_DEFAULT_SHADER_ATTRIB_LOCATION_TANGENT       4
+#endif
+#ifndef RL_DEFAULT_SHADER_ATTRIB_LOCATION_TEXCOORD2
+    #define RL_DEFAULT_SHADER_ATTRIB_LOCATION_TEXCOORD2 5
+#endif
+
 //----------------------------------------------------------------------------------
 // Types and Structures Definition
 //----------------------------------------------------------------------------------
@@ -934,26 +954,6 @@ RLAPI void rlLoadDrawQuad(void);     // Load and draw a quad
     #endif
 #endif
 
-// Default shader vertex attribute locations
-#ifndef RL_DEFAULT_SHADER_ATTRIB_LOCATION_POSITION
-    #define RL_DEFAULT_SHADER_ATTRIB_LOCATION_POSITION  0
-#endif
-#ifndef RL_DEFAULT_SHADER_ATTRIB_LOCATION_TEXCOORD
-    #define RL_DEFAULT_SHADER_ATTRIB_LOCATION_TEXCOORD  1
-#endif
-#ifndef RL_DEFAULT_SHADER_ATTRIB_LOCATION_NORMAL
-    #define RL_DEFAULT_SHADER_ATTRIB_LOCATION_NORMAL    2
-#endif
-#ifndef RL_DEFAULT_SHADER_ATTRIB_LOCATION_COLOR
-    #define RL_DEFAULT_SHADER_ATTRIB_LOCATION_COLOR     3
-#endif
-#ifndef RL_DEFAULT_SHADER_ATTRIB_LOCATION_TANGENT
-    #define RL_DEFAULT_SHADER_ATTRIB_LOCATION_TANGENT   4
-#endif
-#ifndef RL_DEFAULT_SHADER_ATTRIB_LOCATION_TEXCOORD2
-    #define RL_DEFAULT_SHADER_ATTRIB_LOCATION_TEXCOORD2 5
-#endif
-
 // Default shader vertex attribute names to set location points
 #ifndef RL_DEFAULT_SHADER_ATTRIB_NAME_POSITION
     #define RL_DEFAULT_SHADER_ATTRIB_NAME_POSITION     "vertexPosition"    // Bound by default to shader location: RL_DEFAULT_SHADER_ATTRIB_NAME_POSITION