Replace GLEW with a glLoadGen loader.

This should fix the GL loading errors that occur in some drivers due to
the use of deprecated functions by GLEW. Side benefits are more accurate
auto-completion (deprecated function and symbols don't exist) and faster
pointer loading (less entrypoints to load). In addition it removes an
external library depency, simplifying the build system a bit and
eliminating one set of binary libraries for Windows.

src/video_core/renderer_opengl/generated/Readme.md

@@ -0,0 +1,5 @@
+These file were generated by the [glLoadGen](https://bitbucket.org/alfonse/glloadgen/wiki/Home) OpenGL loader generator and have been checked in as-is. You can re-generate them using version 2.0.2 of glLoadGen and executing the following command:
+
+```
+lua LoadGen.lua -version 3.2 -profile core -indent space 3_2_core
+```

src/video_core/renderer_opengl/gl_shader_util.h

@@ -4,7 +4,7 @@
 
 #pragma once
 
-#include <GL/glew.h>
+#include "generated/gl_3_2_core.h"
 
 namespace ShaderUtil {
 

src/video_core/renderer_opengl/renderer_opengl.cpp

@@ -247,10 +247,9 @@ void RendererOpenGL::SetWindow(EmuWindow* window) {
 void RendererOpenGL::Init() {
     render_window->MakeCurrent();
 
-    GLenum err = glewInit();
-    if (GLEW_OK != err) {
-        ERROR_LOG(RENDER, "Failed to initialize GLEW! Error message: \"%s\". Exiting...",
-                  glewGetErrorString(err));
+    int err = ogl_LoadFunctions();
+    if (ogl_LOAD_SUCCEEDED != err) {
+        ERROR_LOG(RENDER, "Failed to initialize GL functions! Exiting...");
         exit(-1);
     }
 
@@ -265,7 +264,6 @@ void RendererOpenGL::Init() {
 
     // Initialize everything else
     // --------------------------
-
     InitFramebuffer();
 
     NOTICE_LOG(RENDER, "GL_VERSION: %s\n", glGetString(GL_VERSION));

src/video_core/renderer_opengl/renderer_opengl.h

@@ -4,7 +4,7 @@
 
 #pragma once
 
-#include <GL/glew.h>
+#include "generated/gl_3_2_core.h"
 
 #include "common/common.h"
 #include "common/emu_window.h"