diff --git a/bootstrap b/bootstrap
index ca72d8f7..0ce931c8 100755
--- a/bootstrap
+++ b/bootstrap
@@ -1,5 +1,6 @@
 #!/bin/sh
-test -n "$BASH_SOURCE" && workdir="${BASH_SOURCE[0]%/*}" && test -n "$workdir" && cd "$workdir" || \
-workdir=`dirname "$0"` && test -n "$workdir" && cd "$workdir" || echo "Warning: can't get working directory" 1>&2
+if ! test -n "$BASH_SOURCE" || ! workdir="${BASH_SOURCE[0]%/*}" || ! test -n "$workdir" || ! cd "$workdir"; then
+  workdir=`dirname "$0"` && test -n "$workdir" && cd "$workdir" || echo "Warning: can't get working directory" 1>&2
+fi
 aclocal -I m4 --install
 autoreconf -I m4 -f -i