Make the open source not opt into omnibus

Summary: Complicated and might go away in the future, so don't inflict it on open source users.

Reviewed By: lmvasquezg

Differential Revision: D42342282

fbshipit-source-id: 3988e3c33fd71fefc37285508cb93a48478c4840

prelude/toolchains/python.bzl

@@ -62,7 +62,7 @@ def _system_python_toolchain_impl(ctx):
             make_pex_inplace = ctx.attrs.make_pex_inplace[RunInfo],
             compile = RunInfo(args = ["echo", "COMPILEINFO"]),
             package_style = "inplace",
-            native_link_strategy = "merged",
+            native_link_strategy = "separate",
         ),
         PythonPlatformInfo(name = "x86_64"),
     ]