[gtk-doc] scan: only copy new sections file if it changed

[Stefan Kost <stefkost src gnome org>]

commit 5ee4e11ddebb85779fb62996ea566a20a0bed2e3
Author: Stefan Sauer <ensonic users sf net>
Date:   Tue May 31 23:09:43 2016 +0200

    scan: only copy new sections file if it changed
    
    Avoids needless rebuilds when people use --rebuild-sections.

 gtkdoc-scan.in |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/gtkdoc-scan.in b/gtkdoc-scan.in
index 26566cf..9f423e8 100755
--- a/gtkdoc-scan.in
+++ b/gtkdoc-scan.in
@@ -193,7 +193,7 @@ EOF
     # we copy the MODULE-decl-list.txt file into its place. The user can tweak it
     # later if they want.
     if ($REBUILD_SECTIONS || ! -e $sections_file) {
-      `cp $old_decl_list $sections_file`;
+      &UpdateFileIfChanged ($sections_file, $old_decl_list, 0);
     }
 
     # If there is no MODULE-overrides.txt file we create an empty one