Surround XR.Tools alias with PAL_TRAIT_BUILD_HOST_TOOLS (#67)

Signed-off-by: moraaar <[email protected]>

Gems/XR/Code/CMakeLists.txt

@@ -78,7 +78,10 @@ ly_add_target(
 
 # use the XR module in clients and tools:
 ly_create_alias(NAME XR.Clients NAMESPACE Gem TARGETS Gem::XR)
-ly_create_alias(NAME XR.Tools NAMESPACE Gem TARGETS Gem::XR)
+
+if(PAL_TRAIT_BUILD_HOST_TOOLS)
+    ly_create_alias(NAME XR.Tools NAMESPACE Gem TARGETS Gem::XR)
+endif()
 
 ################################################################################
 # Tests