disable bundled dependencies

Index: CMakeLists.txt
--- CMakeLists.txt.orig
+++ CMakeLists.txt
@@ -120,7 +120,7 @@ endif(MSVC)
 
 # Configure subdirectories.
 # We depend on these for later projects, so they should come first.
-add_subdirectory(third_party)
+# add_subdirectory(third_party)
 
 add_subdirectory(libshaderc_util)
 add_subdirectory(libshaderc)