Added warning about not using Config for single-object options.

src/Config

+##############################################################################
+##############################################################################
+#
+# IMPORTANT!
+# 
+# This file is deprecated.  All options are gradually being migrated
+# to config.h.  Only options that affect the entire build
+# (e.g. overriding the $(CC) Makefile variable) should be placed in
+# here.
+#
+##############################################################################
+##############################################################################
+
+
 #
 # Config for Etherboot/32
 #
+#
 # Do not delete the tag OptionDescription and /OptionDescription
 # It is used to automatically generate the documentation.
 #

src/arch/i386/Config

+##############################################################################
+##############################################################################
+#
+# IMPORTANT!
+# 
+# The use of this file to set options that affect only single object
+# files is deprecated, because changing anything in this file results
+# in a complete rebuild, which is slow.  All options are gradually
+# being migrated to config.h, which does not suffer from this problem.
+# 
+# Only options that affect the entire build (e.g. overriding the $(CC)
+# Makefile variable) should be placed in here.
+#
+##############################################################################
+##############################################################################
+
+
 # Config for i386 Etherboot
 #
 # Do not delete the tag OptionDescription and /OptionDescription
 # LCONFIG+=	-DBBS_BUT_NOT_PNP_COMPLIANT
 # LCONFIG+=	-DBOOT_INT18H
 
-# Produce code that will work inside the Bochs emulator.  The pnic
-# driver is probably the best one to try.
-# CFLAGS+=	-DCONFIG_PCI_DIRECT
-
 # Produce code that will work with OpenBSD's pxeboot
 # CFLAGS+=	-DFLATTEN_REAL_MODE