[pan2] file::get_pan_home() : fix for g++-5 non-CoW std::string semantics

[Petr Kovář <pmkovar src gnome org>]

commit 34e1bb5f76bc0026091a6f494c354b0064e8ace0
Author: Alexandre Rostovtsev <tetromino gentoo org>
Date:   Mon Sep 7 13:21:22 2015 -0400

    file::get_pan_home() : fix for g++-5 non-CoW std::string semantics
    
    https://bugzilla.gnome.org/show_bug.cgi?id=754698

 pan/general/file-util.cc |    2 +-
 pan/general/file-util.h  |    2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/pan/general/file-util.cc b/pan/general/file-util.cc
index 4ea2e77..473e426 100644
--- a/pan/general/file-util.cc
+++ b/pan/general/file-util.cc
@@ -77,7 +77,7 @@ file :: print_file_info (std::ostream& os, const char* file)
 ****
 ***/
 
-std::string
+const std::string &
 file :: get_pan_home ()
 {
   static std::string pan_home;
diff --git a/pan/general/file-util.h b/pan/general/file-util.h
index 7c211a8..4b6d04f 100644
--- a/pan/general/file-util.h
+++ b/pan/general/file-util.h
@@ -59,7 +59,7 @@ namespace pan
      * Returns the home pan directory, which falls back to $HOME/.pan2
      * if the PAN_HOME environmental variable isn't set.
      */
-    std::string get_pan_home ();
+    const std::string & get_pan_home ();
 
     /**
         * Returns an absolute filename of a file