dropped f32xbase dependency on Makefile.common

This means that we only depend on f32xbase for atusb-sil (defunct) and
cntr (needs updating), but not for any of the project's main parts.

- makefiles/Makefile.basic: copied over from
  f32xbase/lib/Makefile.common
- makefiles/Makefile.basic (LDLIBS): removed inclusion of libusb
- tools/Makefile.common: use makefiles/Makefile.basic
- install/INSTALL-Ben, prod/doc/setup.hmac: removed f32xbase
  dependency

makefiles/Makefile.basic

@@ -0,0 +1,37 @@
+#
+# Makefile.basic - Basic makefile for single-executable builds
+#
+# Written 2008, 2011 by Werner Almesberger
+# Copyright 2008, 2011 Werner Almesberger
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+
+
+INSTALL_PREFIX = /usr/local
+
+CFLAGS = -Wall
+LDFLAGS =
+LDLIBS =
+
+.PHONY:		all install uninstall clean spotless
+
+all:		$(MAIN)
+
+$(MAIN):	$(MAIN).o $(OBJS)
+		$(CC) $(CFLAGS) $(LDFLAGS) -o $@ $(MAIN).o $(OBJS) $(LDLIBS)
+
+install:	$(MAIN)
+		install $(MAIN) $(INSTALL_PREFIX)/bin/
+
+uninstall:
+		rm -f $(INSTALL_PREFIX)/bin/$(MAIN)
+
+clean::
+		rm -f $(MAIN).o $(OBJS)
+
+spotless:	clean
+		rm -f $(MAIN)