Re-run libtoolize from libtool-2.2.6 and follow its suggestions.

--HG--
branch : HEAD
diff --git a/Makefile.am b/Makefile.am
index a25b86c..4e41d3f 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -1,6 +1,8 @@
 # not GPL, thus no COPYING
 AUTOMAKE_OPTIONS=dist-bzip2 foreign
 
+ACLOCAL_AMFLAGS=	-I m4
+
 SUBDIRS=lib src man regress
 
 pkgconfigdir = $(libdir)/pkgconfig