Print the VK error code (#237)

If the device fails to be created and the error is not recorginzied, the
error message impossible to act on. If we output the error number, then
the user can look it up, and see what needs to be done.

---------

Co-authored-by: Chris B <[email protected]>

Author: s-perron

lib/API/VK/Device.cpp

@@ -836,7 +836,8 @@ class VKContext {
                                      "Cannot find a compatible Vulkan device");
     if (Res)
       return llvm::createStringError(std::errc::no_such_device,
-                                     "Unknown Vulkan initialization error");
+                                     "Unknown Vulkan initialization error: %d",
+                                     Res);
 
     uint32_t DeviceCount = 0;
     if (vkEnumeratePhysicalDevices(Instance, &DeviceCount, nullptr))
@@ -867,7 +868,8 @@ class VKContext {
                                      "Cannot find a compatible Vulkan device");
     if (Res)
       return llvm::createStringError(std::errc::no_such_device,
-                                     "Unknown Vulkan initialization error");
+                                     "Unknown Vulkan initialization error %d",
+                                     Res);
 
     DeviceCount = 0;
     if (vkEnumeratePhysicalDevices(Instance, &DeviceCount, nullptr))