RSPRO: Add ErrorInd

Change-Id: I5e5e227d188c5f30ae9be60dd0439ae6f6913b8a
diff --git a/include/osmocom/rspro/Makefile.am b/include/osmocom/rspro/Makefile.am
index f189c0a..41df9dc 100644
--- a/include/osmocom/rspro/Makefile.am
+++ b/include/osmocom/rspro/Makefile.am
@@ -17,6 +17,10 @@
 	ConnectClientRes.h \
 	CreateMappingReq.h \
 	CreateMappingRes.h \
+	ErrorCode.h \
+	ErrorInd.h \
+	ErrorSeverity.h \
+	ErrorString.h \
 	IpAddress.h \
 	IpPort.h \
 	Ipv4Address.h \