Build fix for x11_egl target builds
Build fix for x11_egl target builds

The combination of recent refactor on release branch and merge to
master resulted in a compilation error for the XInitThreads symbol
when using the x11_egl built target.

Components: Framework

VK-GL-CTS Issue: 467

Change-Id: Iba0803e8b73462bd66ab7803a6c90bfd40d9164c

KhronosGroup/Vulkan-CTS,KhronosGroup/VK-GL-CTS,KhronosGroup/VK-GL-CTS,KhronosGroup/Vulkan-CTS,googlestadia/VK-GL-CTS,KhronosGroup/Vulkan-CTS,KhronosGroup/VK-GL-CTS,KhronosGroup/VK-GL-CTS,KhronosGroup/VK-GL-CTS,googlestadia/VK-GL-CTS,KhronosGroup/Vulkan-CTS,KhronosGroup/Vulkan-CTS,googlestadia/VK-GL-CTS,KhronosGroup/Vulkan-CTS,googlestadia/VK-GL-CTS,googlestadia/VK-GL-CTS,KhronosGroup/VK-GL-CTS,googlestadia/VK-GL-CTS