Fix recursive try_compile calls

When building an entire source tree with try_compile instead of just a
single source file, it is possible that the CMakeLists.txt file in the
try-compiled project invokes try_compile.  This commit fixes propagation
of language-initialization results from the outer-most project into any
number of try-compile levels.

Source/cmGlobalGenerator.cxx

@@ -1343,9 +1343,7 @@ cmLocalGenerator *cmGlobalGenerator::CreateLocalGenerator()
 
 void cmGlobalGenerator::EnableLanguagesFromGenerator(cmGlobalGenerator *gen )
 {
-  std::string cfp = gen->GetCMakeInstance()->GetHomeOutputDirectory();
-  cfp += cmake::GetCMakeFilesDirectory();
-  this->SetConfiguredFilesPath(cfp.c_str());
+  this->SetConfiguredFilesPath(gen);
   const char* make =
     gen->GetCMakeInstance()->GetCacheDefinition("CMAKE_MAKE_PROGRAM");
   this->GetCMakeInstance()->AddCacheEntry("CMAKE_MAKE_PROGRAM", make,
@@ -1360,6 +1358,20 @@ void cmGlobalGenerator::EnableLanguagesFromGenerator(cmGlobalGenerator *gen )
   this->OutputExtensions = gen->OutputExtensions;
 }
 
+//----------------------------------------------------------------------------
+void cmGlobalGenerator::SetConfiguredFilesPath(cmGlobalGenerator* gen)
+{
+  if(!gen->ConfiguredFilesPath.empty())
+    {
+    this->ConfiguredFilesPath = gen->ConfiguredFilesPath;
+    }
+  else
+    {
+    this->ConfiguredFilesPath = gen->CMakeInstance->GetHomeOutputDirectory();
+    this->ConfiguredFilesPath += cmake::GetCMakeFilesDirectory();
+    }
+}
+
 //----------------------------------------------------------------------------
 void cmGlobalGenerator::GetDocumentation(cmDocumentationEntry& entry) const
 {

Source/cmGlobalGenerator.h

@@ -123,7 +123,7 @@ public:
   ///! Get the CMake instance
   cmake *GetCMakeInstance() { return this->CMakeInstance; };
 
-  void SetConfiguredFilesPath(const char* s){this->ConfiguredFilesPath = s;}
+  void SetConfiguredFilesPath(cmGlobalGenerator* gen);
   const std::vector<cmLocalGenerator *>& GetLocalGenerators() const { 
     return this->LocalGenerators;}
 

Tests/TryCompile/Inner/CMakeLists.txt

@@ -1,4 +1,13 @@
 cmake_minimum_required(VERSION 2.6)
 project(TryCompileInner C)
 
+try_compile(SHOULD_PASS
+    ${TryCompileInner_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeTmp
+    ${TryCompileInner_SOURCE_DIR}/../pass.c
+    OUTPUT_VARIABLE TRY_OUT
+    )
+if(NOT SHOULD_PASS)
+  message(FATAL_ERROR "Inner try-compile SHOULD_PASS failed!")
+endif()
+
 add_executable(inner ../pass.c)