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, 12 insertions, 0 deletions

diff --git a/Source/cmGetPropertyCommand.cxx b/Source/cmGetPropertyCommand.cxx
index 985dc50..faba7cd 100644
--- a/Source/cmGetPropertyCommand.cxx
+++ b/Source/cmGetPropertyCommand.cxx
@@ -288,6 +288,18 @@ bool cmGetPropertyCommand::HandleTargetMode()
     return false;
     }
 
+  if(this->PropertyName == "ALIASED_TARGET")
+    {
+    if(this->Makefile->IsAlias(this->Name.c_str()))
+      {
+      if(cmTarget* target =
+                          this->Makefile->FindTargetToUse(this->Name.c_str()))
+        {
+        return this->StoreResult(target->GetName());
+        }
+      }
+    return false;
+    }
   if(cmTarget* target = this->Makefile->FindTargetToUse(this->Name.c_str()))
     {
     return this->StoreResult(target->GetProperty(this->PropertyName.c_str()));