diff --git a/CMakeLists.txt b/CMakeLists.txt
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -112,7 +112,12 @@
 
 # Configure subdirectories.
 # We depend on these for later projects, so they should come first.
-add_subdirectory(third_party)
+find_package(glslang REQUIRED CONFIG)
+find_package(SPIRV-Headers REQUIRED CONFIG)
+find_package(SPIRV-Tools REQUIRED CONFIG)
+set(glslang_SOURCE_DIR ${glslang_INCLUDE_DIRS})
+set(SPIRV-Headers_SOURCE_DIR ${SPIRV-Headers_INCLUDE_DIR}/..)
+set(spirv-tools_SOURCE_DIR ${SPIRV-Tools_INCLUDE_DIR}/..)
 
 add_subdirectory(libshaderc_util)
 add_subdirectory(libshaderc)