configure.ac: Intentionally underquote m4_normalize calls

This works around a bug in Autoconf 2.64 and earlier, which generated
ridiculous symbols like
  /* #undef HAVE_M4_NORMALIZE___FCNTL_H__LANGINFO_H__LIMITS_H__… */
instead of the ones we need.  It was fixed by v2.65~21:
  http://git.savannah.gnu.org/gitweb/?p=autoconf.git;a=commitdiff;h=81c80d1bf6c8ddf732d0b89f6fc5e306dac9705e

Signed-off-by: Anders Kaseorg <andersk@mit.edu>
My own configure file (for Mac OS).
Update my_configure with all debug options.
Make the waiting time for attaching gdb an option.
Make not-detaching server mode an option.
Add a library to retrieve the host source addresses.
Add a C++ abstraction for managing Addresses.
Addr infrastructure for having flows.

A flow is defined by an address source and an address destination.
Migrate flow related fields in Flow objects.
Import my logger.
Add flow id and flags to the protocol.
Allow making empty family-specific addresses.
Only make generic IPV6 hybrid sockets.

We ignore the desired IP because we will explicitly specify
the outgoing address.
Add function to send packets with desired IP address.
Ask for the local address used on packet reception.
Track the last couple of (src, dst) to send message (server).
Import my logger (2).
Switch sendfromto arguments.
Implement probing functions.
Remove useless remote_addr_len variable.