Don't allow include() of export(EXPORT) file at configure time.

As a new feature it does not need to participate in CMP0024.

Store cmExportBuildFileGenerator instances which correspond to the
export(EXPORT) signature in a second map which does not own the
pointers.  This avoids the need to add cmExportBuildFileGenerator
and dependencies to the bootstrap system.

Source/cmExportCommand.cxx

@@ -236,8 +236,14 @@ bool cmExportCommand
     {
     ebfg->AddConfiguration("");
     }
-
-  gg->AddBuildExportSet(ebfg);
+  if (this->ExportSet)
+    {
+    gg->AddBuildExportExportSet(ebfg);
+    }
+  else
+    {
+    gg->AddBuildExportSet(ebfg);
+    }
 
   return true;
 }

Source/cmGlobalGenerator.cxx

@@ -187,6 +187,13 @@ void cmGlobalGenerator::AddBuildExportSet(cmExportBuildFileGenerator* gen)
   this->BuildExportSets[gen->GetMainExportFileName()] = gen;
 }
 
+void
+cmGlobalGenerator::AddBuildExportExportSet(cmExportBuildFileGenerator* gen)
+{
+  this->BuildExportSets[gen->GetMainExportFileName()] = gen;
+  this->BuildExportExportSets[gen->GetMainExportFileName()] = gen;
+}
+
 bool cmGlobalGenerator::GenerateImportFile(const std::string &file)
 {
   std::map<std::string, cmExportBuildFileGenerator*>::iterator it
@@ -207,7 +214,12 @@ cmGlobalGenerator::IsExportedTargetsFile(const std::string &filename) const
 {
   const std::map<std::string, cmExportBuildFileGenerator*>::const_iterator it
                                       = this->BuildExportSets.find(filename);
-  return it != this->BuildExportSets.end();
+  if (it == this->BuildExportSets.end())
+    {
+    return false;
+    }
+  return this->BuildExportExportSets.find(filename)
+                                        == this->BuildExportExportSets.end();
 }
 
 // Find the make program for the generator, required for try compiles

Source/cmGlobalGenerator.h

@@ -311,6 +311,7 @@ public:
   std::map<std::string, cmExportBuildFileGenerator*>& GetBuildExportSets()
     {return this->BuildExportSets;}
   void AddBuildExportSet(cmExportBuildFileGenerator*);
+  void AddBuildExportExportSet(cmExportBuildFileGenerator*);
   bool IsExportedTargetsFile(const std::string &filename) const;
   bool GenerateImportFile(const std::string &file);
   cmExportBuildFileGenerator*
@@ -375,6 +376,7 @@ protected:
   // Sets of named target exports
   cmExportSetMap ExportSets;
   std::map<std::string, cmExportBuildFileGenerator*> BuildExportSets;
+  std::map<std::string, cmExportBuildFileGenerator*> BuildExportExportSets;
 
   // Manifest of all targets that will be built for each configuration.
   // This is computed just before local generators generate.

Tests/RunCMake/include/ExportExportInclude-result.txt

@@ -0,0 +1 @@
+1

Tests/RunCMake/include/ExportExportInclude-stderr.txt

@@ -0,0 +1,6 @@
+CMake Error at ExportExportInclude.cmake:6 \(include\):
+  include could not find load file:
+
+    .*/Tests/RunCMake/include/ExportExportInclude-build/theTargets.cmake
+Call Stack \(most recent call first\):
+  CMakeLists.txt:3 \(include\)

Tests/RunCMake/include/ExportExportInclude.cmake

@@ -0,0 +1,6 @@
+
+add_library(iface INTERFACE)
+install(TARGETS iface EXPORT ifaceExport)
+
+export(EXPORT ifaceExport FILE "${CMAKE_CURRENT_BINARY_DIR}/theTargets.cmake")
+include("${CMAKE_CURRENT_BINARY_DIR}/theTargets.cmake")

Tests/RunCMake/include/RunCMakeTest.cmake

@@ -4,3 +4,4 @@ run_cmake(EmptyString)
 run_cmake(EmptyStringOptional)
 run_cmake(CMP0024-WARN)
 run_cmake(CMP0024-NEW)
+run_cmake(ExportExportInclude)