Add the ALIAS target concept for libraries and executables.

* The ALIAS name must match a validity regex.
* Executables and libraries may be aliased.
* An ALIAS acts immutable. It can not be used as the lhs
  of target_link_libraries or other commands.
* An ALIAS can be used with add_custom_command, add_custom_target,
  and add_test in the same way regular targets can.
* The target of an ALIAS can be retrieved with the ALIASED_TARGET
  target property.
* An ALIAS does not appear in the generated buildsystem. It
  is kept separate from cmMakefile::Targets for that reason.
* A target may have multiple aliases.
* An ALIAS target may not itself have an alias.
* An IMPORTED target may not have an alias.
* An ALIAS may not be exported or imported.

1 files changed, 5 insertions, 0 deletions

diff --git a/Source/cmSetTargetPropertiesCommand.cxx b/Source/cmSetTargetPropertiesCommand.cxx
index a2b50a8eff..78ef393cc7 100644
--- a/Source/cmSetTargetPropertiesCommand.cxx
+++ b/Source/cmSetTargetPropertiesCommand.cxx
@@ -72,6 +72,11 @@ bool cmSetTargetPropertiesCommand
   int i;
   for(i = 0; i < numFiles; ++i)
     {
+    if (this->Makefile->IsAlias(args[i].c_str()))
+      {
+      this->SetError("can not be used on an ALIAS target.");
+      return false;
+      }
     bool ret = cmSetTargetPropertiesCommand::SetOneTarget
       (args[i].c_str(),propertyPairs,this->Makefile);
     if (!ret)