ui/app: call main from Android and iOS

Android can only run c-shared libraries which means that every
Gio program must create its window and event loop from an init
function.

The same applies to iOS but for a more benign reason: the gio tool
builds programs in c-archive mode for iOS and links the binary with
a Objective-C driver.

Allow Gio programs to run off its main function by linking to and
invoking main even from Android libraries and iOS ditto.

Signed-off-by: Elias Naur <mail@eliasnaur.com>

ui/app/gl_macos.m

@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: Unlicense OR MIT
 
-//+build darwin,!ios
+// +build darwin,!ios
 
 @import AppKit;