ENH: Enforce unique binary directories

The second argument of add_subdirectory must name a unique binary
directory or the build files will clobber each other.  This enforces
uniqueness with an error message.

1 files changed, 4 insertions, 0 deletions

diff --git a/Source/cmGlobalGenerator.cxx b/Source/cmGlobalGenerator.cxx
index 4fc26f60db..0103a855b8 100644
--- a/Source/cmGlobalGenerator.cxx
+++ b/Source/cmGlobalGenerator.cxx
@@ -732,18 +732,22 @@ void cmGlobalGenerator::Configure()
   this->ProjectMap.clear();
   this->RuleHashes.clear();
   this->DirectoryContentMap.clear();
+  this->BinaryDirectories.clear();
 
   // start with this directory
   cmLocalGenerator *lg = this->CreateLocalGenerator();
   this->LocalGenerators.push_back(lg);
 
   // set the Start directories
+  cmMakefile* mf = lg->GetMakefile();
   lg->GetMakefile()->SetStartDirectory
     (this->CMakeInstance->GetStartDirectory());
   lg->GetMakefile()->SetStartOutputDirectory
     (this->CMakeInstance->GetStartOutputDirectory());
   lg->GetMakefile()->MakeStartDirectoriesCurrent();
 
+  this->BinaryDirectories.insert(mf->GetStartOutputDirectory());
+
   // now do it
   lg->Configure();