Create an m4 directory for common macros and use it.

Split acinclude.m4 in multiple macro files.

Let it be known to autoconf and aclocal to use the m4 directory.
Ignore macro files copied or linked by libtool and intltool.

m4/acx_libwrap.m4

@@ -0,0 +1,19 @@
+AC_DEFUN([ACX_LIBWRAP], [
+LIBWRAP_LIBS=
+saved_LIBS="$LIBS"
+LIBS="$LIBS -lwrap"
+AC_MSG_CHECKING([for tcpwrap library and headers])
+AC_LINK_IFELSE(
+AC_LANG_PROGRAM(
+[#include <tcpd.h>
+#include <syslog.h>
+int allow_severity = LOG_INFO;
+int deny_severity = LOG_WARNING;],
+[struct request_info *req;
+return hosts_access (req);]),
+[AC_DEFINE(HAVE_LIBWRAP, [], [Have tcpwrap?])
+LIBWRAP_LIBS="-lwrap"
+AC_MSG_RESULT(yes)],
+[AC_MSG_RESULT(no)])
+LIBS="$saved_LIBS"
+])