add libiu

Co-Authored by dwillmann, laforge, nhofmeyr

Change-Id: Iffc26f9c73cb15463948f7435b72ac1747aabdb3
diff --git a/openbsc/src/Makefile.am b/openbsc/src/Makefile.am
index 6f6174e..4aa880f 100644
--- a/openbsc/src/Makefile.am
+++ b/openbsc/src/Makefile.am
@@ -2,9 +2,18 @@
 AM_CFLAGS=-Wall $(LIBOSMOCORE_CFLAGS) $(LIBOSMOGSM_CFLAGS) $(LIBOSMOGSM_CFLAGS) $(LIBOSMOVTY_CFLAGS) $(COVERAGE_CFLAGS)
 AM_LDFLAGS = $(LIBOSMOCORE_LIBS) $(LIBOSMOGSM_LIBS) $(COVERAGE_LDFLAGS)
 
-SUBDIRS = libcommon libmgcp libbsc libmsc libtrau libfilter osmo-nitb osmo-bsc_mgcp utils ipaccess gprs
+# Libraries
+SUBDIRS = libcommon libmgcp libbsc libmsc libtrau libfilter
 
-# Conditional modules
+# Conditional Libraries
+if BUILD_IU
+SUBDIRS += libiu
+endif
+
+# Programs
+SUBDIRS += osmo-nitb osmo-bsc_mgcp utils ipaccess gprs
+
+# Conditional Programs
 if BUILD_NAT
 SUBDIRS += osmo-bsc_nat
 endif