internal/vk: [Android] add workaround for Vulkan on the emulator

According to the Vulkan specification the pApplicationInfo member of
the VkInstanceCreateInfo structure may be NULL. However, the Android
emulator crashes on vkEnumeratePhysicalDevices if set to NULL.
This change adds a minimal info to please the emulator.

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

internal/vk/vulkan.go

@@ -823,8 +823,19 @@ func CreateInstance(exts ...string) (Instance, error) {
 	if err := vkInit(); err != nil {
 		return nil, err
 	}
+	// VK_MAKE_API_VERSION macro.
+	makeVer := func(variant, major, minor, patch int) C.uint32_t {
+		return ((((C.uint32_t)(variant)) << 29) | (((C.uint32_t)(major)) << 22) | (((C.uint32_t)(minor)) << 12) | ((C.uint32_t)(patch)))
+	}
+	appInf := C.VkApplicationInfo{
+		sType:      C.VK_STRUCTURE_TYPE_APPLICATION_INFO,
+		apiVersion: makeVer(0, 1, 0, 0),
+	}
 	inf := C.VkInstanceCreateInfo{
 		sType: C.VK_STRUCTURE_TYPE_INSTANCE_CREATE_INFO,
+		// pApplicationInfo may be omitted according to the spec, but the Android
+		// emulator crashes without it.
+		pApplicationInfo: &appInf,
 	}
 	if len(exts) > 0 {
 		cexts := mallocCStringArr(exts)