Avoid duplicate RPATH entries

Teach cmComputeLinkInformation::GetRPath to avoid adding the same
directory to the output runtime path more than once.

Source/cmComputeLinkInformation.cxx

@@ -1751,6 +1751,22 @@ cmComputeLinkInformation::AddLibraryRuntimeInfo(std::string const& fullPath)
     }
 }
 
+//----------------------------------------------------------------------------
+static void cmCLI_ExpandListUnique(const char* str,
+                                   std::vector<std::string>& out,
+                                   std::set<cmStdString>& emitted)
+{
+  std::vector<std::string> tmp;
+  cmSystemTools::ExpandListArgument(str, tmp);
+  for(std::vector<std::string>::iterator i = tmp.begin(); i != tmp.end(); ++i)
+    {
+    if(emitted.insert(*i).second)
+      {
+      out.push_back(*i);
+      }
+    }
+}
+
 //----------------------------------------------------------------------------
 void cmComputeLinkInformation::GetRPath(std::vector<std::string>& runtimeDirs,
                                         bool for_install)
@@ -1776,10 +1792,11 @@ void cmComputeLinkInformation::GetRPath(std::vector<std::string>& runtimeDirs,
     this->Target->GetPropertyAsBool("INSTALL_RPATH_USE_LINK_PATH");
 
   // Construct the RPATH.
+  std::set<cmStdString> emitted;
   if(use_install_rpath)
     {
     const char* install_rpath = this->Target->GetProperty("INSTALL_RPATH");
-    cmSystemTools::ExpandListArgument(install_rpath, runtimeDirs);
+    cmCLI_ExpandListUnique(install_rpath, runtimeDirs, emitted);
     }
   if(use_build_rpath || use_link_rpath)
     {
@@ -1791,7 +1808,10 @@ void cmComputeLinkInformation::GetRPath(std::vector<std::string>& runtimeDirs,
       // support or if using the link path as an rpath.
       if(use_build_rpath)
         {
-        runtimeDirs.push_back(*ri);
+        if(emitted.insert(*ri).second)
+          {
+          runtimeDirs.push_back(*ri);
+          }
         }
       else if(use_link_rpath)
         {
@@ -1803,7 +1823,10 @@ void cmComputeLinkInformation::GetRPath(std::vector<std::string>& runtimeDirs,
            !cmSystemTools::IsSubDirectory(ri->c_str(), topSourceDir) &&
            !cmSystemTools::IsSubDirectory(ri->c_str(), topBinaryDir))
           {
-          runtimeDirs.push_back(*ri);
+          if(emitted.insert(*ri).second)
+            {
+            runtimeDirs.push_back(*ri);
+            }
           }
         }
       }
@@ -1811,7 +1834,7 @@ void cmComputeLinkInformation::GetRPath(std::vector<std::string>& runtimeDirs,
 
   // Add runtime paths required by the platform to always be
   // present.  This is done even when skipping rpath support.
-  cmSystemTools::ExpandListArgument(this->RuntimeAlways.c_str(), runtimeDirs);
+  cmCLI_ExpandListUnique(this->RuntimeAlways.c_str(), runtimeDirs, emitted);
 }
 
 //----------------------------------------------------------------------------