Platform: fix {Sdl2,Glfw}Application startup on GL-less builds.

src/Magnum/Platform/GlfwApplication.cpp

@@ -67,7 +67,11 @@ GlfwApplication::GlfwApplication(const Arguments& arguments, NoCreateT):
     #ifdef MAGNUM_TARGET_GL
     _context.reset(new GLContext{NoCreate, args, arguments.argc, arguments.argv});
     #else
-    args.parse(arguments.argc, arguments.argv);
+    /** @todo this is duplicated here and in Sdl2Application, figure out a nice
+        non-duplicated way to handle this */
+    args.addOption("log", "default").setHelp("log", "console logging", "default|quiet|verbose")
+        .setFromEnvironment("log")
+        .parse(arguments.argc, arguments.argv);
     #endif
 
     /* Init GLFW */

src/Magnum/Platform/Sdl2Application.cpp

@@ -91,7 +91,11 @@ Sdl2Application::Sdl2Application(const Arguments& arguments, NoCreateT):
     #ifdef MAGNUM_TARGET_GL
     _context.reset(new GLContext{NoCreate, args, arguments.argc, arguments.argv});
     #else
-    args.parse(arguments.argc, arguments.argv);
+    /** @todo this is duplicated here and in Sdl2Application, figure out a nice
+        non-duplicated way to handle this */
+    args.addOption("log", "default").setHelp("log", "console logging", "default|quiet|verbose")
+        .setFromEnvironment("log")
+        .parse(arguments.argc, arguments.argv);
     #endif
 
     /* Available since 2.0.4, disables interception of SIGINT and SIGTERM so