Make sure all files under the new shared dir are included in make dist.

git-svn-id: svn://svn.valgrind.org/valgrind/trunk@13868 a5019735-40e9-0310-863c-91ae7b9d1cf9
diff --git a/Makefile.am b/Makefile.am
index 40e2b0f..2426b5c 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -25,6 +25,7 @@
 	. \
 	$(TOOLS) \
 	$(EXP_TOOLS) \
+	shared \
 	tests \
 	perf \
 	gdbserver_tests \