exports: accept a missing target if it is exported exactly once

If a target is exported, and a library it depends on is not part
of the same export set, before this patch cmake errored out.
With this patch, it now checks whether the missing target
is exported somewhere else exactly once, and accepts in this
case (because then it can determine the namespace for the
missing target and use this).

Alex

1 files changed, 13 insertions, 3 deletions

diff --git a/Source/cmExportInstallFileGenerator.cxx b/Source/cmExportInstallFileGenerator.cxx
index d4f7fd5..ba048b5 100644
--- a/Source/cmExportInstallFileGenerator.cxx
+++ b/Source/cmExportInstallFileGenerator.cxx
@@ -327,14 +327,24 @@ cmExportInstallFileGenerator
 //----------------------------------------------------------------------------
 void
 cmExportInstallFileGenerator
-::ComplainAboutMissingTarget(cmTarget* depender, cmTarget* dependee)
+::ComplainAboutMissingTarget(cmTarget* depender,
+                             cmTarget* dependee,
+                             int occurrences)
 {
   cmOStringStream e;
   e << "INSTALL(EXPORT \""
     << this->IEGen->GetExportSet()->GetName()
     << "\" ...) "
     << "includes target \"" << depender->GetName()
-    << "\" which requires target \"" << dependee->GetName()
-    << "\" that is not in the export set.";
+    << "\" which requires target \"" << dependee->GetName() << "\" ";
+  if (occurrences == 0)
+    {
+    e << "that is not in the export set.";
+    }
+  else
+    {
+    e << "that is not in this export set, but " << occurrences
+    << " times in others.";
+    }
   cmSystemTools::Error(e.str().c_str());
 }