diff --git a/Makefile.in b/Makefile.in
index a794d41..9f82a9f 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -86,7 +86,7 @@
 am__include = @am__include@
 am__quote = @am__quote@
 install_sh = @install_sh@
-SUBDIRS = gtp ggsn sgsnemu
+SUBDIRS = gtp ggsn sgsnemu doc
 subdir = .
 ACLOCAL_M4 = $(top_srcdir)/aclocal.m4
 mkinstalldirs = $(SHELL) $(top_srcdir)/mkinstalldirs