diff --git a/docs/libnm/Makefile.am b/docs/libnm/Makefile.am
index e04d1722b..28938f89f 100644
--- a/docs/libnm/Makefile.am
+++ b/docs/libnm/Makefile.am
@@ -10,7 +10,11 @@ DOC_MAIN_SGML_FILE=$(DOC_MODULE)-docs.xml
 # The directory containing the source code. Relative to $(srcdir).
 # gtk-doc will search all .c & .h files beneath here for inline comments
 # documenting functions and macros.
-DOC_SOURCE_DIR=$(top_srcdir)/libnm-core $(top_srcdir)/libnm
+DOC_SOURCE_DIR= \
+	$(top_srcdir)/libnm-core \
+	$(top_builddir)/libnm-core \
+	$(top_srcdir)/libnm \
+	$(top_builddir)/libnm
 
 # Extra options to supply to gtkdoc-scan.
 SCAN_OPTIONS=--rebuild-types --rebuild-sections