From 1777570fe5eb194d930f6716865bc909269da57e Mon Sep 17 00:00:00 2001
From: Brad King <brad.king@kitware.com>
Date: Mon, 19 Sep 2016 15:30:34 -0400
Subject: [PATCH] cmGeneratorTarget: Refactor Fortran module directory lookup

Make `target_module_dir` and owned value so we can modify it.
---
 Source/cmGeneratorTarget.cxx | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/Source/cmGeneratorTarget.cxx b/Source/cmGeneratorTarget.cxx
index 1e21ac492..bed0b115a 100644
--- a/Source/cmGeneratorTarget.cxx
+++ b/Source/cmGeneratorTarget.cxx
@@ -3896,10 +3896,13 @@ std::string cmGeneratorTarget::GetFortranModuleDirectory() const
 std::string cmGeneratorTarget::CreateFortranModuleDirectory() const
 {
   std::string mod_dir;
-  const char* target_mod_dir = this->GetProperty("Fortran_MODULE_DIRECTORY");
+  std::string target_mod_dir;
+  if (const char* prop = this->GetProperty("Fortran_MODULE_DIRECTORY")) {
+    target_mod_dir = prop;
+  }
   const char* moddir_flag =
     this->Makefile->GetDefinition("CMAKE_Fortran_MODDIR_FLAG");
-  if (target_mod_dir && moddir_flag) {
+  if (!target_mod_dir.empty() && moddir_flag) {
     // Compute the full path to the module directory.
     if (cmSystemTools::FileIsFullPath(target_mod_dir)) {
       // Already a full path.