From 9cfe4f1b769597bd9ba179eba46572a9df27f64c Mon Sep 17 00:00:00 2001
From: Stephen Kelly <steveire@gmail.com>
Date: Mon, 26 Nov 2012 12:30:00 +0100
Subject: [PATCH] Allow target_link_libraries with IMPORTED targets.

This makes it possible to use:

 target_link_libraries(foo LINK_INTERFACE_LIBRARIES bar)

where foo is an IMPORTED target. Other tll() signatures are not
allowed.
---
 Source/cmTargetLinkLibrariesCommand.cxx            | 14 ++++++++++++++
 .../target_link_libraries/CMakeLists.txt           |  3 +++
 2 files changed, 17 insertions(+)

diff --git a/Source/cmTargetLinkLibrariesCommand.cxx b/Source/cmTargetLinkLibrariesCommand.cxx
index f42b0f687..0705fb4d6 100644
--- a/Source/cmTargetLinkLibrariesCommand.cxx
+++ b/Source/cmTargetLinkLibrariesCommand.cxx
@@ -33,6 +33,10 @@ bool cmTargetLinkLibrariesCommand
   this->Target =
     this->Makefile->GetCMakeInstance()
     ->GetGlobalGenerator()->FindTarget(0, args[0].c_str());
+  if(!this->Target)
+    {
+    this->Target = this->Makefile->FindTargetToUse(args[0].c_str());
+    }
   if(!this->Target)
     {
     cmake::MessageType t = cmake::FATAL_ERROR;  // fail by default
@@ -257,6 +261,16 @@ cmTargetLinkLibrariesCommand::HandleLibrary(const char* lib,
   // Handle normal case first.
   if(this->CurrentProcessingState != ProcessingLinkInterface)
     {
+    if (this->Target->IsImported())
+      {
+      cmOStringStream e;
+      e << "Imported targets may only be used with the "
+          "LINK_INTERFACE_LIBRARIES specifier to target_link_libraries.";
+      this->Makefile->IssueMessage(cmake::FATAL_ERROR, e.str());
+      return;
+      }
+
+
     this->Makefile
       ->AddLinkLibraryForTarget(this->Target->GetName(), lib, llt);
     if (this->CurrentProcessingState != ProcessingPublicInterface)
diff --git a/Tests/CMakeCommands/target_link_libraries/CMakeLists.txt b/Tests/CMakeCommands/target_link_libraries/CMakeLists.txt
index 60b36fc27..e586c28d9 100644
--- a/Tests/CMakeCommands/target_link_libraries/CMakeLists.txt
+++ b/Tests/CMakeCommands/target_link_libraries/CMakeLists.txt
@@ -29,6 +29,9 @@ set(CMAKE_INCLUDE_CURRENT_DIR ON)
 add_library(depA SHARED depA.cpp)
 generate_export_header(depA)
 
+add_library(importedlib UNKNOWN IMPORTED)
+target_link_libraries(importedlib LINK_INTERFACE_LIBRARIES depA)
+
 add_library(depB SHARED depB.cpp)
 generate_export_header(depB)