diff --git a/doc/Makefile.am b/doc/Makefile.am
index fd46fc1..d261473 100644
--- a/doc/Makefile.am
+++ b/doc/Makefile.am
@@ -49,7 +49,6 @@ CLEANFILES = index.html
 
 if HAVE_DOCUMENTA
 api/index.texi: $(API_SOURCES)
-	$(AM_V_GEN)$(top_builddir)/pre-inst-env		\
-	  $(DOCUMENTA) api -d $(srcdir)/api		\
-	  $(top_srcdir)/safsaf.scm $(top_srcdir)/safsaf/
+	cd $(top_srcdir) && ./pre-inst-env	\
+	  $(DOCUMENTA) api "safsaf.scm safsaf/"
 endif