Fix running autogen.sh out-of-tree
As done in GNOME's jhbuild building tool.
https://bugzilla.libsdl.org/show_bug.cgi?id=3374
diff --git a/autogen.sh b/autogen.sh
index 649d7b3..3e958e1 100755
--- a/autogen.sh
+++ b/autogen.sh
@@ -3,6 +3,10 @@
echo "Generating build information using autoconf"
echo "This may take a while ..."
+srcdir=`dirname $0`
+test -z "$srcdir" && srcdir=.
+pushd $srcdir
+
# Regenerate configuration files
cat acinclude/* >aclocal.m4
found=false
@@ -15,5 +19,7 @@
fi
(cd test; sh autogen.sh)
+popd
+
# Run configure for this platform
echo "Now you are ready to run ./configure"
