Description: Preprocess sources before documentation generation
 This fixes FTBFS.

diff --git a/rebar.config b/rebar.config
index 9780e57..493eb6e 100644
--- a/rebar.config
+++ b/rebar.config
@@ -1,2 +1,3 @@
 {deps, [
-]}.
+]}.
+{edoc_opts, [{preprocess, true}]}.
