diff --git a/Makefile.am b/Makefile.am
--- a/Makefile.am
+++ b/Makefile.am
@@ -20,7 +20,7 @@ libdistrencommon_la_SOURCES = src/common
 	src/common/execio.c src/common/execio.h \
 	src/common/misc.c src/common/misc.h \
 	src/common/options.c src/common/options.h \
-	src/common/protocol.h \
+	src/common/protocol.c src/common/protocol.h \
 	src/common/remoteio.h \
 	src/common/remoteio.c src/common/libremoteio.h
 #see http://sources.redhat.com/autobook/autobook/autobook_91.html