Fix RPATH information when only a genex is used as a link library.

As of commit 1da75022 (Don't include generator expressions in
old-style link handling., 2012-12-23), such entries are not
included in the LinkLibraries member. Generator expressions in
LinkLibraries are not processed anyway, so port to the new way
of getting link information.

Source/cmComputeLinkInformation.cxx

@@ -1816,7 +1816,7 @@ void cmComputeLinkInformation::GetRPath(std::vector<std::string>& runtimeDirs,
     (outputRuntime && this->Target->HaveInstallTreeRPATH() &&
      linking_for_install);
   bool use_build_rpath =
-    (outputRuntime && this->Target->HaveBuildTreeRPATH() &&
+    (outputRuntime && this->Target->HaveBuildTreeRPATH(this->Config) &&
      !linking_for_install);
   bool use_link_rpath =
     outputRuntime && linking_for_install &&

Source/cmTarget.cxx

@@ -4253,10 +4253,15 @@ void cmTarget::SetPropertyDefault(const char* property,
 }
 
 //----------------------------------------------------------------------------
-bool cmTarget::HaveBuildTreeRPATH()
+bool cmTarget::HaveBuildTreeRPATH(const char *config)
 {
-  return (!this->GetPropertyAsBool("SKIP_BUILD_RPATH") &&
-          !this->LinkLibraries.empty());
+  if (this->GetPropertyAsBool("SKIP_BUILD_RPATH"))
+    {
+    return false;
+    }
+  std::vector<std::string> libs;
+  this->GetDirectLinkLibraries(config, libs, this);
+  return !libs.empty();
 }
 
 //----------------------------------------------------------------------------
@@ -4327,7 +4332,7 @@ bool cmTarget::NeedRelinkBeforeInstall(const char* config)
   // If either a build or install tree rpath is set then the rpath
   // will likely change between the build tree and install tree and
   // this target must be relinked.
-  return this->HaveBuildTreeRPATH() || this->HaveInstallTreeRPATH();
+  return this->HaveBuildTreeRPATH(config) || this->HaveInstallTreeRPATH();
 }
 
 //----------------------------------------------------------------------------

Source/cmTarget.h

@@ -401,7 +401,7 @@ public:
    */
   bool NeedRelinkBeforeInstall(const char* config);
 
-  bool HaveBuildTreeRPATH();
+  bool HaveBuildTreeRPATH(const char *config);
   bool HaveInstallTreeRPATH();
 
   /** Return true if builtin chrpath will work for this target */