Build X11 parts only for ozone_platform_x11

Bug: swiftshader:175
Bug: chromium:578890
Change-Id: Ia8564397083cf6d5ffc4bf40a62ccb3a4db1068e
Co-authored-by: Maksim Sisov <msisov@igalia.com>
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/67008
Reviewed-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>
Commit-Queue: Yaroslav Isakov <yaroslav.isakov@gmail.com>
Tested-by: Nicolas Capens <nicolascapens@google.com>
diff --git a/src/Vulkan/BUILD.gn b/src/Vulkan/BUILD.gn
index e782a3f..5556abd 100644
--- a/src/Vulkan/BUILD.gn
+++ b/src/Vulkan/BUILD.gn
@@ -14,6 +14,7 @@
 
 import("//build_overrides/build.gni")
 import("//build_overrides/wayland.gni")
+import("//build/config/ozone.gni")
 import("../swiftshader.gni")
 import("vulkan.gni")
 
@@ -21,9 +22,11 @@
 config("swiftshader_libvulkan_private_config") {
   if (is_linux) {
     defines = [
-      "VK_USE_PLATFORM_XCB_KHR",
       "VK_EXPORT=__attribute__((visibility(\"default\")))",
     ]
+    if (ozone_platform_x11) {
+      defines += [ "VK_USE_PLATFORM_XCB_KHR" ]
+    }
     if (ozone_platform_wayland) {
       defines += [ "VK_USE_PLATFORM_WAYLAND_KHR" ]
     }
diff --git a/src/WSI/BUILD.gn b/src/WSI/BUILD.gn
index 3910345..4709332 100644
--- a/src/WSI/BUILD.gn
+++ b/src/WSI/BUILD.gn
@@ -14,6 +14,7 @@
 
 import("../swiftshader.gni")
 import("//build_overrides/wayland.gni")
+import("//build/config/ozone.gni")
 
 config("WSI_metal_weak_framework") {
   if (is_mac) {
@@ -35,12 +36,14 @@
   ]
 
   if (is_linux) {
-    sources += [
-      "XcbSurfaceKHR.cpp",
-      "XcbSurfaceKHR.hpp",
-      "libXCB.cpp",
-      "libXCB.hpp",
-    ]
+    if (ozone_platform_x11) {
+      sources += [
+        "XcbSurfaceKHR.cpp",
+        "XcbSurfaceKHR.hpp",
+        "libXCB.cpp",
+        "libXCB.hpp",
+      ]
+    }
 
     if (ozone_platform_wayland) {
       sources += [