[gnome-sudoku/gnome-3-18] Fix autogen with srcdir != builddir

[Michael Catanzaro <mcatanzaro src gnome org>]

commit 28260999d4b24039d40550dff76ecf56f73963b1
Author: Michael Catanzaro <mcatanzaro gnome org>
Date:   Sat Jul 30 10:42:09 2016 -0500

    Fix autogen with srcdir != builddir

 autogen.sh |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/autogen.sh b/autogen.sh
index 6e8332a..e94809f 100755
--- a/autogen.sh
+++ b/autogen.sh
@@ -1,6 +1,9 @@
 #!/bin/sh
 # Run this to generate all the initial makefiles, etc.
 
+test -n "$srcdir" || srcdir=`dirname "$0"`
+test -n "$srcdir" || srcdir=.
+
 which gnome-autogen.sh || {
     echo "You need to install gnome-common from GNOME git (or from"
     echo "your OS vendor's package manager)."