Do proper typecasting so this compiles on IRIX

--HG--
extra : convert_revision : svn%3Ac70aab31-4412-0410-b14c-859654838e24/trunk%40181

src/video/x11/SDL_x11gl.c

@@ -360,15 +360,23 @@ int X11_GL_LoadLibrary(_THIS, const char* path)
 	X11_GL_UnloadLibrary(this);
 
 	/* Load new function pointers */
-	this->gl_data->glXGetProcAddress = dlsym(handle, "glXGetProcAddressARB");
-	this->gl_data->glXChooseVisual = dlsym(handle, "glXChooseVisual");
-	this->gl_data->glXCreateContext = dlsym(handle, "glXCreateContext");
-	this->gl_data->glXDestroyContext = dlsym(handle, "glXDestroyContext");
-	this->gl_data->glXMakeCurrent = dlsym(handle, "glXMakeCurrent");
-	this->gl_data->glXSwapBuffers = dlsym(handle, "glXSwapBuffers");
-	this->gl_data->glXGetConfig = dlsym(handle, "glXGetConfig");
+	this->gl_data->glXGetProcAddress =
+		(void *(*)(const GLubyte *)) dlsym(handle, "glXGetProcAddressARB");
+	this->gl_data->glXChooseVisual =
+		(XVisualInfo *(*)(Display *, int, int *)) dlsym(handle, "glXChooseVisual");
+	this->gl_data->glXCreateContext =
+		(GLXContext (*)(Display *, XVisualInfo *, GLXContext, int)) dlsym(handle, "glXCreateContext");
+	this->gl_data->glXDestroyContext =
+		(void (*)(Display *, GLXContext)) dlsym(handle, "glXDestroyContext");
+	this->gl_data->glXMakeCurrent =
+		(int (*)(Display *, GLXDrawable, GLXContext)) dlsym(handle, "glXMakeCurrent");
+	this->gl_data->glXSwapBuffers =
+		(void (*)(Display *, GLXDrawable)) dlsym(handle, "glXSwapBuffers");
+	this->gl_data->glXGetConfig =
+		(int (*)(Display *, XVisualInfo *, int, int *)) dlsym(handle, "glXGetConfig");
 	/* We don't compare below for this in case we're not using Mesa. */
-	this->gl_data->glXReleaseBuffersMESA = dlsym( handle, "glXReleaseBuffersMESA" );
+	this->gl_data->glXReleaseBuffersMESA =
+		(void (*)(Display *, GLXDrawable)) dlsym( handle, "glXReleaseBuffersMESA" );
 
 	if ( (this->gl_data->glXChooseVisual == NULL) || 
 	     (this->gl_data->glXCreateContext == NULL) ||