Switch llvmcpy to overlay convention

.orchestra/config/components.yml

 #@ load("@ytt:template", "template")
 #@ load("@ytt:data", "data")
 
-#@ load("/components/llvmcpy.lib.yml", "llvmcpy_component")
 #@ load("/components/clang_release.lib.yml", "clang_release_component")
 #@ load("/components/glib.lib.yml", "glib_component")
 #@ load("/components/glibc.lib.yml", "glibc_component")
@@ -46,7 +45,6 @@
 
 #@ load("/global_options.lib.yml", "options")
 components:
-  llvmcpy: #@ llvmcpy_component
   clang-release: #@ clang_release_component
   glib: #@ glib_component
   glibc: #@ glibc_component

.orchestra/config/components/llvmcpy.lib.yml → .orchestra/config/components/llvmcpy.yml

+#@ load("@ytt:overlay", "overlay")
+
 #@ def _llvmcpy_component():
 repository: llvmcpy
 builds:
@@ -14,5 +16,8 @@ builds:
       python3 setup.py build --build-base "$SOURCE_DIR" install --home "$DESTDIR"
 #@ end
 
+#@overlay/match by=overlay.all, expects=1
+#@overlay/match-child-defaults missing_ok=True
 ---
-#@ llvmcpy_component = _llvmcpy_component()
+components:
+  llvmcpy: #@ _llvmcpy_component()