Add support for plugins (and specifically GPRS encryption plugins)
diff --git a/include/osmocom/Makefile.am b/include/osmocom/Makefile.am
index 71293d1..fd9074c 100644
--- a/include/osmocom/Makefile.am
+++ b/include/osmocom/Makefile.am
@@ -1,3 +1,5 @@
 if ENABLE_VTY
-SUBDIRS = vty
+SUBDIRS = vty crypt
+else
+SUBDIRS = crypt
 endif