Group libraries when linking with gcc

visual_studio/NativeClientVSAddIn/NaCl.Build.CPPTasks/NaClLink.cs

 
 using System;
 using System.IO;
 using System.Resources;
 using System.Reflection;
 using System.Text;
 using Microsoft.Build.Framework;
 using Microsoft.Build.CPPTasks;
 
 
@@ skipping 59 matching lines @@
 
         protected override void LogEventsFromTextOutput(string singleLine, MessageImportance messageImportance)
         {
             base.LogEventsFromTextOutput(GCCUtilities.ConvertGCCOutput(singleLine), messageImportance);
         }
 
         protected override string GenerateResponseFileCommands()
         {
             StringBuilder responseFileCmds = new StringBuilder(GCCUtilities.s_CommandLineLength);
 
+            // We want GCC to behave more like visual studio in term of library dependencies
+            // so we wrap all the inputs (libraries and object) into one group so they are
+            // searched iteratively.
+            responseFileCmds.Append("-Wl,--start-group ");
             foreach (ITaskItem sourceFile in Sources)
             {
                 responseFileCmds.Append(GCCUtilities.ConvertPathWindowsToPosix(sourceFile.GetMetadata("Identity")));
                 responseFileCmds.Append(" ");
             }
+            responseFileCmds.Append("-Wl,--end-group ");
 
             responseFileCmds.Append(m_XamlParser.Parse(Sources[0], false));
 
             return responseFileCmds.ToString();
         }
 
         public override bool Execute()
         {
             bool returnResult = false;
 
@@ skipping 91 matching lines @@
             {
                 return "GCC";
             }
             set
             {}
         }  
 
         public string TrackerLogDirectory { get; set; }
         }
 }