From 34a990946c655a0be69e4168461c5e23a2d64bfa Mon Sep 17 00:00:00 2001
From: Stephen Kelly <steveire@gmail.com>
Date: Thu, 8 Jan 2015 15:20:38 -0500
Subject: [PATCH] get_target_property: discern empty from undefined properties
 (#15333)

This was accidentally regressed by commit v3.1.0-rc1~812^2~50
(stringapi: Use strings for property names, 2013-09-02).
---
 Source/cmGetTargetPropertyCommand.cxx | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/Source/cmGetTargetPropertyCommand.cxx b/Source/cmGetTargetPropertyCommand.cxx
index aa6f0c11cc..fb59df8fc7 100644
--- a/Source/cmGetTargetPropertyCommand.cxx
+++ b/Source/cmGetTargetPropertyCommand.cxx
@@ -23,6 +23,7 @@ bool cmGetTargetPropertyCommand
   std::string var = args[0];
   const std::string& targetName = args[1];
   std::string prop;
+  bool prop_exists = false;
 
   if(args[2] == "ALIASED_TARGET")
     {
@@ -32,6 +33,7 @@ bool cmGetTargetPropertyCommand
                           this->Makefile->FindTargetToUse(targetName))
         {
         prop = target->GetName();
+        prop_exists = true;
         }
       }
     }
@@ -42,6 +44,7 @@ bool cmGetTargetPropertyCommand
     if(prop_cstr)
       {
       prop = prop_cstr;
+      prop_exists = true;
       }
     }
   else
@@ -74,7 +77,7 @@ bool cmGetTargetPropertyCommand
         }
       }
     }
-  if (!prop.empty())
+  if (prop_exists)
     {
     this->Makefile->AddDefinition(var, prop.c_str());
     return true;