Fix bashism in autogen.sh

https://bugzilla.gnome.org/show_bug.cgi?id=780215

autogen.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/bin/sh
 # Run this to generate all the initial makefiles, etc.
 
 srcdir=`dirname $0`
@@ -6,7 +6,9 @@ test -z "$srcdir" && srcdir=.
 
 REQUIRED_AUTOMAKE_VERSION=1.11
 
-pushd $srcdir
+olddir="$(pwd)"
+
+cd "${srcdir}"
 
 (test -f configure.ac \
   && test -d src) || {
@@ -19,8 +21,8 @@ aclocal --install || exit 1
 intltoolize --force --copy --automake || exit 1
 autoreconf --verbose --force --install || exit 1
 
-popd
+cd "${olddir}"
 
 if [ "$NOCONFIGURE" = "" ]; then
-    $srcdir/configure "$@" || exit 1
+    "${srcdir}/configure" "$@" || exit 1
 fi