--- a/src/third_party/SConscript	2019-09-22 14:31:48.847382840 +0200
+++ b/src/third_party/SConscript	2019-09-22 14:32:56.858997243 +0200
@@ -188,7 +188,7 @@
     libraries = thisEnv.Flatten([libraries])
     parts = thisEnv.Flatten([parts])
     for lib in libraries:
-        mods = thirdPartyEnvironmentModifications[lib]
+        mods = thirdPartyEnvironmentModifications.get(lib, {})
         if not parts:
             thisEnv.PrependUnique(**mods)
         else: