[GLExtensions] Remove AGL GetProcAddress. Change dlsym to using RTLD_NEXT. Enable dlsym fallback for OS X

Source/Core/DolphinWX/GLInterface/AGL.cpp

@@ -21,37 +21,16 @@
 #include "ConfigManager.h"
 
 #include <wx/panel.h>
-#import <mach-o/dyld.h> 
 
 #include "VertexShaderManager.h"
 #include "../GLInterface.h"
 #include "AGL.h"
 
-// Copied from
-// https://developer.apple.com/library/mac/documentation/graphicsimaging/conceptual/opengl-macprogguide/opengl_entrypts/opengl_entrypts.html
-void* NSGLGetProcAddress (const char *name)
-{
-	NSSymbol symbol;
-	char* symbolName;
-	symbolName = (char*)malloc(strlen (name) + 2); // 1
-	strcpy(symbolName + 1, name); // 2
-	symbolName[0] = '_'; // 3
-	symbol = NULL;
-	if (NSIsSymbolNameDefined (symbolName)) // 4
-		symbol = NSLookupAndBindSymbol (symbolName);
-	free (symbolName); // 5
-	return symbol ? NSAddressOfSymbol (symbol) : NULL; // 6
-}
-
 void cInterfaceAGL::Swap()
 {
 	[GLWin.cocoaCtx flushBuffer];
 }
 
-void* cInterfaceAGL::GetProcAddress(std::string name)
-{
-	return NSGLGetProcAddress(name.c_str());
-}
 // Create rendering window.
 //		Call browser: Core.cpp:EmuThread() > main.cpp:Video_Initialize()
 bool cInterfaceAGL::Create(void *&window_handle)

Source/Core/DolphinWX/GLInterface/AGL.h

@@ -27,7 +27,6 @@ class cInterfaceAGL : public cInterfaceBase
 {
 public:
 	void Swap();
-	void* GetProcAddress(std::string name);
 	bool Create(void *&window_handle);
 	bool MakeCurrent();
 	bool ClearCurrent();

Source/Core/VideoBackends/OGL/GLExtensions/GLExtensions.cpp

@@ -773,7 +773,6 @@ PFNGLNAMEDBUFFERSTORAGEEXTPROC glNamedBufferStorageEXT;
 namespace GLExtensions
 {
 	// Private members and functions
-	void *_dlsym;
 	bool _isES3;
 	bool _isES;
 	u32 _GLVersion;
@@ -846,10 +845,9 @@ namespace GLExtensions
 		*func = GLInterface->GetProcAddress(name);
 		if (*func == NULL)
 		{
-#if defined(__linux__)
+#if defined(__linux__) || defined(__APPLE__)
 			// Give it a second try with dlsym
-			if (_dlsym) // Just in case dlopen fails
-				*func = dlsym(_dlsym, name.c_str());
+			*func = dlsym(RTLD_NEXT, name.c_str());
 #endif
 			if (*func == NULL && _isES)
 				*func = (void*)0xFFFFFFFF; // Easy to determine invalid function, just so we continue on
@@ -869,9 +867,6 @@ namespace GLExtensions
 	bool Init()
 	{
 		bool success = true;
-#if defined(__linux__)
-		_dlsym = dlopen(NULL, RTLD_LAZY);
-#endif
 		_isES3 = GLInterface->GetMode() == GLInterfaceMode::MODE_OPENGLES3;
 		_isES = GLInterface->GetMode() == GLInterfaceMode::MODE_OPENGLES3 || GLInterface->GetMode() == GLInterfaceMode::MODE_OPENGLES2;
 
@@ -913,9 +908,6 @@ namespace GLExtensions
 		if (success && !init_khr_debug()) success = false;
 		if (success && !init_arb_buffer_storage()) success = false;
 
-#if defined(__linux__)
-		dlclose(_dlsym);
-#endif
 		return success;
 	}