Silence a spurious warning about the SDK location when debugging Swift code on Linux.

rdar://108765542

Author: adrian-prantl

lldb/include/lldb/Host/linux/HostInfoLinux.h

@@ -30,6 +30,12 @@ class HostInfoLinux : public HostInfoPosix {
   static llvm::StringRef GetDistributionId();
   static FileSpec GetProgramFileSpec();
 
+  static llvm::Expected<llvm::StringRef> GetSDKRoot(SDKOptions options) {
+    if (options.XcodeSDK && options.XcodeSDK->GetType() == XcodeSDK::Type::Linux)
+      return "/";
+    return llvm::make_error<HostInfoError>("cannot determine SDK root");
+  }
+
 protected:
   static bool ComputeSupportExeDirectory(FileSpec &file_spec);
   static bool ComputeSystemPluginsDirectory(FileSpec &file_spec);