--- a/lib/ToolDrivers/llvm-lib/Options.td	Sun Dec 23 19:23:36 2018 +0900
+++ b/lib/ToolDrivers/llvm-lib/Options.td	Wed Aug 14 19:46:37 2019 +0900
@@ -3,23 +3,33 @@
 // lib.exe accepts options starting with either a dash or a slash.
 
 // Flag that takes no arguments.
-class F<string name> : Flag<["/", "-", "-?"], name>;
+class F<string name> : Flag<["/", "-", "/?", "-?"], name>;
 
 // Flag that takes one argument after ":".
 class P<string name, string help> :
-      Joined<["/", "-", "-?"], name#":">, HelpText<help>;
+      Joined<["/", "-", "/?", "-?"], name#":">, HelpText<help>;
 
 def libpath: P<"libpath", "Object file search path">;
+
+// Can't be called "list" since that's a keyword.
+def lst    : F<"list">, HelpText<"List contents of .lib file on stdout">;
 def out    : P<"out", "Path to file to write output">;
 
-def llvmlibthin : F<"llvmlibthin">;
+def llvmlibthin : F<"llvmlibthin">,
+    HelpText<"Make .lib point to .obj files instead of copying their contents">;
+
+def machine: P<"machine", "Specify target platform">;
+
+def help : F<"help">;
+
+// /?? and -?? must be before /? and -? to not confuse lib/Options.
+def help_q : Flag<["/??", "-??", "/?", "-?"], "">, Alias<help>;
 
 //==============================================================================
 // The flags below do nothing. They are defined only for lib.exe compatibility.
 //==============================================================================
 
-class QF<string name> : Joined<["/", "-", "-?"], name#":">;
+class QF<string name> : Joined<["/", "-", "/?", "-?"], name#":">;
 
 def ignore : QF<"ignore">;
-def machine: QF<"machine">;
 def nologo : F<"nologo">;