Fix lookup of an ALIAS target outside aliased target's directory (#16044)

Refactoring in commit v3.5.0-rc1~272^2~11 (cmTarget: Implement ALIAS in
terms of name mapping, 2015-10-25) accidentally introduced logic that
assumes ALIAS targets always reference targets in their own directory.
Fix this and add a test case.

The configure-step fix is that `cmMakefile::FindTarget` should not consider
aliases.  The purpose of this method is just to look up targets local to
a directory.  Since ALIAS and normal targets share a namespace we know a
locally defined target will never collide with an ALIAS target anyway.
The method has 3 call sites, and this change is safe for all of them:

* `cmInstallCommand::HandleTargetsMode`: Rejects aliases before the call.
* `cmFLTKWrapUICommand::FinalPass`: Should never have considered aliases.
* `cmMakefile::FindTargetToUse`: Falls back to a global lookup anyway.

The generate-step fix is that `cmLocalGenerator::FindGeneratorTarget`
should not consider aliases.  This method is the generate-step
equivalent to the above.  The method has 2 call sites, and this change
is safe for both of them:

* `cmInstallTargetGenerator::Compute`: Never uses an alias target name.
* `cmLocalGenerator::FindGeneratorTargetToUse`: Falls back to global lookup.

Reported-by: Matteo Settenvini <matteo@member.fsf.org>

1 files changed, 1 insertions, 2 deletions

diff --git a/Source/cmMakefile.h b/Source/cmMakefile.h
index 362ea75..a69c705 100644
--- a/Source/cmMakefile.h
+++ b/Source/cmMakefile.h
@@ -388,8 +388,7 @@ public:
     }
   std::vector<cmTarget*> GetImportedTargets() const;
 
-  cmTarget* FindTarget(const std::string& name,
-                       bool excludeAliases = false) const;
+  cmTarget* FindTarget(const std::string& name) const;
 
   /** Find a target to use in place of the given name.  The target
       returned may be imported or built within the project.  */