Revert "Use rustdoc --document-private-item instead of deprecated flags"

This reverts commit d96f0ff6a7.

etc/rustdoc-with-private

@@ -0,0 +1,4 @@
+#!/bin/sh
+# Skip the strip-private and strip-hidden rustdoc passes
+# https://github.com/rust-lang/rust/issues/15347
+rustdoc --no-defaults --passes collapse-docs --passes unindent-comments --passes strip-priv-imports "$@"

python/servo/command_base.py

@@ -388,7 +388,7 @@ class CommandBase(object):
                                   " --release" if release else ""))
         sys.exit()
 
-    def build_env(self, hosts_file_path=None, target=None, is_build=False, geckolib=False):
+    def build_env(self, hosts_file_path=None, target=None, is_build=False, geckolib=False, test_unit=False):
         """Return an extended environment dictionary."""
         env = os.environ.copy()
         if sys.platform == "win32" and type(env['PATH']) == unicode:
@@ -486,7 +486,10 @@ class CommandBase(object):
         if hosts_file_path:
             env['HOST_FILE'] = hosts_file_path
 
-        env['RUSTDOCFLAGS'] = "--document-private-items"
+        if not test_unit:
+            # This wrapper script is in bash and doesn't work on Windows
+            # where we want to run doctests as part of `./mach test-unit`
+            env['RUSTDOC'] = path.join(self.context.topdir, 'etc', 'rustdoc-with-private')
 
         if self.config["build"]["rustflags"]:
             env['RUSTFLAGS'] = env.get('RUSTFLAGS', "") + " " + self.config["build"]["rustflags"]

python/servo/testing_commands.py

@@ -255,12 +255,9 @@ class MachCommands(CommandBase):
 
         packages.discard('stylo')
 
-        env = self.build_env()
+        env = self.build_env(test_unit=True)
         env["RUST_BACKTRACE"] = "1"
 
-        # Work around https://github.com/rust-lang/cargo/issues/4790
-        del env["RUSTDOCFLAGS"]
-
         if "msvc" in host_triple():
             # on MSVC, we need some DLLs in the path. They were copied
             # in to the servo.exe build dir, so just point PATH to that.