gfxstream: add back in VK_USE_PLATFORM_SCREEN_QNX for QNX build

Also, resolve TODOs.

BUG=319510663
TEST=compile

Change-Id: I6a44b5ae1875bf6048b1172ffd570a6952413393
diff --git a/host/CMakeLists.txt b/host/CMakeLists.txt
index 2d63bc4..21119b2 100644
--- a/host/CMakeLists.txt
+++ b/host/CMakeLists.txt
@@ -318,8 +318,7 @@
     if (APPLE)
         target_compile_definitions(Vulkan_unittests PRIVATE -DVK_USE_PLATFORM_METAL_EXT)
     elseif (QNX)
-        # TODO(jsimonot): fix build error
-        # target_compile_definitions(Vulkan_unittests PRIVATE -DVK_USE_PLATFORM_SCREEN_QNX)
+        target_compile_definitions(Vulkan_unittests PRIVATE -DVK_USE_PLATFORM_SCREEN_QNX)
     elseif (UNIX)
         target_compile_definitions(Vulkan_unittests PRIVATE -DVK_USE_PLATFORM_XCB_KHR)
     endif()
diff --git a/host/vulkan/CMakeLists.txt b/host/vulkan/CMakeLists.txt
index 183ec75..80e6ab1 100644
--- a/host/vulkan/CMakeLists.txt
+++ b/host/vulkan/CMakeLists.txt
@@ -42,8 +42,7 @@
 elseif (APPLE)
 target_compile_definitions(gfxstream-vulkan-server PRIVATE -DVK_USE_PLATFORM_METAL_EXT)
 elseif (QNX)
-# TODO(jsimonot): fix build error
-# target_compile_definitions(gfxstream-vulkan-server PRIVATE -DVK_USE_PLATFORM_SCREEN_QNX)
+target_compile_definitions(gfxstream-vulkan-server PRIVATE -DVK_USE_PLATFORM_SCREEN_QNX)
 endif()
 
 if (NOT MSVC)
diff --git a/host/vulkan/meson.build b/host/vulkan/meson.build
index 744f84c..955810c 100644
--- a/host/vulkan/meson.build
+++ b/host/vulkan/meson.build
@@ -48,8 +48,7 @@
 elif host_machine.system() == 'windows'
   vulkan_server_cpp_args += '-DVK_USE_PLATFORM_WIN32_KHR'
 elif host_machine.system() == 'qnx'
-## TODO: jsimonot: resolve vk header issue
-#  vulkan_server_cpp_args += '-DVK_USE_PLATFORM_SCREEN_QNX'
+  vulkan_server_cpp_args += '-DVK_USE_PLATFORM_SCREEN_QNX'
 endif
 
 lib_vulkan_server = static_library(