Pacify some GCC strict-aliasing compiler warnings.

src/render/opengl/SDL_render_gl.c

@@ -493,7 +493,7 @@ GL_CreateRenderer(SDL_Window * window, Uint32 flags)
         PFNGLDEBUGMESSAGECALLBACKARBPROC glDebugMessageCallbackARBFunc = (PFNGLDEBUGMESSAGECALLBACKARBPROC) SDL_GL_GetProcAddress("glDebugMessageCallbackARB");
 
         data->GL_ARB_debug_output_supported = SDL_TRUE;
-        data->glGetPointerv(GL_DEBUG_CALLBACK_FUNCTION_ARB, (GLvoid **)&data->next_error_callback);
+        data->glGetPointerv(GL_DEBUG_CALLBACK_FUNCTION_ARB, (GLvoid **)(char *)&data->next_error_callback);
         data->glGetPointerv(GL_DEBUG_CALLBACK_USER_PARAM_ARB, &data->next_error_userparam);
         glDebugMessageCallbackARBFunc(GL_HandleDebugMessage, renderer);
 

src/render/opengles2/SDL_render_gles2.c

@@ -1068,7 +1068,7 @@ GLES2_CacheShader(SDL_Renderer *renderer, GLES2_ShaderType type, SDL_BlendMode b
     /* Compile or load the selected shader instance */
     entry->id = data->glCreateShader(instance->type);
     if (instance->format == (GLenum)-1) {
-        data->glShaderSource(entry->id, 1, (const char **)&instance->data, NULL);
+        data->glShaderSource(entry->id, 1, (const char **)(char *)&instance->data, NULL);
         data->glCompileShader(entry->id);
         data->glGetShaderiv(entry->id, GL_COMPILE_STATUS, &compileSuccessful);
     } else {

src/video/SDL_shape.c

@@ -234,10 +234,10 @@ void
 SDL_FreeShapeTree(SDL_ShapeTree** shape_tree)
 {
     if((*shape_tree)->kind == QuadShape) {
-        SDL_FreeShapeTree((SDL_ShapeTree **)&(*shape_tree)->data.children.upleft);
-        SDL_FreeShapeTree((SDL_ShapeTree **)&(*shape_tree)->data.children.upright);
-        SDL_FreeShapeTree((SDL_ShapeTree **)&(*shape_tree)->data.children.downleft);
-        SDL_FreeShapeTree((SDL_ShapeTree **)&(*shape_tree)->data.children.downright);
+        SDL_FreeShapeTree((SDL_ShapeTree **)(char*)&(*shape_tree)->data.children.upleft);
+        SDL_FreeShapeTree((SDL_ShapeTree **)(char*)&(*shape_tree)->data.children.upright);
+        SDL_FreeShapeTree((SDL_ShapeTree **)(char*)&(*shape_tree)->data.children.downleft);
+        SDL_FreeShapeTree((SDL_ShapeTree **)(char*)&(*shape_tree)->data.children.downright);
     }
     SDL_free(*shape_tree);
     *shape_tree = NULL;