build: let autogen.sh script change into top source directory

Acked-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: Thomas Haller <thaller@redhat.com>

autogen.sh

@@ -1,6 +1,15 @@
 #!/bin/bash
 
-autoreconf -fi;
+die() {
+    echo "$@" >&2
+    exit 1
+}
+
+BASEDIR="$(dirname "$0")"
+
+cd "$BASEDIR" || die "Could not change into base directory $BASEDIR"
+
+autoreconf -fi || die "Error during autoreconf"
 rm -Rf autom4te.cache;
 
-doc/autogen.sh
+doc/autogen.sh || die "Error during doc/autogen.sh"