Adapt to API change that moved Sysroot attribute to CompileUnit

Commit 7b30370 changed the Sysroot
attribute to the CompileUnit which broke the build.

Author: Teemperor

lib/IRGen/IRGenDebugInfo.cpp

@@ -659,10 +659,8 @@ class IRGenDebugInfoImpl : public IRGenDebugInfo {
       }
     }
 
-    StringRef Sysroot = IGM.Context.SearchPathOpts.SDKPath;
     llvm::DIModule *M =
-        DBuilder.createModule(Parent, Name, ConfigMacros, RemappedIncludePath,
-                              Sysroot);
+        DBuilder.createModule(Parent, Name, ConfigMacros, RemappedIncludePath);
     DIModuleCache.insert({Key, llvm::TrackingMDNodeRef(M)});
     return M;
   }
@@ -1692,6 +1690,7 @@ IRGenDebugInfoImpl::IRGenDebugInfoImpl(const IRGenOptions &Opts,
       DBuilder.createFile(DebugPrefixMap.remapPath(SourcePath),
                           DebugPrefixMap.remapPath(Opts.DebugCompilationDir));
 
+  StringRef Sysroot = IGM.Context.SearchPathOpts.SDKPath;
   TheCU = DBuilder.createCompileUnit(
       Lang, MainFile,
       Producer, Opts.shouldOptimize(), Opts.getDebugFlags(PD),
@@ -1702,7 +1701,7 @@ IRGenDebugInfoImpl::IRGenDebugInfoImpl(const IRGenOptions &Opts,
       /* DWOId */ 0, /* SplitDebugInlining */ true,
       /* DebugInfoForProfiling */ false,
       llvm::DICompileUnit::DebugNameTableKind::Default,
-      /* RangesBaseAddress */ false);
+      /* RangesBaseAddress */ false, Sysroot);
 
   // Because the swift compiler relies on Clang to setup the Module,
   // the clang CU is always created first.  Several dwarf-reading