libatomic: Enable AM_MAINTAINER_MODE

From-SVN: r187108
diff --git a/libatomic/configure.ac b/libatomic/configure.ac
index 18d1dea..1b4f325 100644
--- a/libatomic/configure.ac
+++ b/libatomic/configure.ac
@@ -144,6 +144,7 @@
 AM_PROG_LIBTOOL
 AC_SUBST(enable_shared)
 AC_SUBST(enable_static)
+AM_MAINTAINER_MODE
 
 # For libtool versioning info, format is CURRENT:REVISION:AGE
 libtool_VERSION=1:0:0