documentation: remove smart-config.txt

As requested by Sam Ravnborg: Remove Documentation/smart-config.txt.

It is outdated and has been (functionally) replaced by
Documentation/kbuild/*.txt.
Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Documentation/00-INDEX

@@ -329,8 +329,6 @@ sgi-visws.txt
 	- short blurb on the SGI Visual Workstations.
 sh/
 	- directory with info on porting Linux to a new architecture.
-smart-config.txt
-	- description of the Smart Config makefile feature.
 sound/
 	- directory with info on sound card support.
 sparc/

Documentation/smart-config.txt

-Smart CONFIG_* Dependencies
-1 August 1999
-
-Michael Chastain   <mec@shout.net>
-Werner Almesberger <almesber@lrc.di.epfl.ch>
-Martin von Loewis  <martin@mira.isdn.cs.tu-berlin.de>
-
-Here is the problem:
-
-    Suppose that drivers/net/foo.c has the following lines:
-
-	#include <linux/config.h>
-
-	...
-
-	#ifdef CONFIG_FOO_AUTOFROB
-	    /* Code for auto-frobbing */
-	#else
-	    /* Manual frobbing only */
-	#endif
-
-	...
-
-	#ifdef CONFIG_FOO_MODEL_TWO
-	    /* Code for model two */
-	#endif
-
-    Now suppose the user (the person building kernels) reconfigures the
-    kernel to change some unrelated setting.  This will regenerate the
-    file include/linux/autoconf.h, which will cause include/linux/config.h
-    to be out of date, which will cause drivers/net/foo.c to be recompiled.
-
-    Most kernel sources, perhaps 80% of them, have at least one CONFIG_*
-    dependency somewhere.  So changing _any_ CONFIG_* setting requires
-    almost _all_ of the kernel to be recompiled.
-
-Here is the solution:
-
-    We've made the dependency generator, mkdep.c, smarter.  Instead of
-    generating this dependency:
-
-	drivers/net/foo.c: include/linux/config.h
-
-    It now generates these dependencies:
-
-	drivers/net/foo.c: \
-	    include/config/foo/autofrob.h \
-	    include/config/foo/model/two.h
-
-    So drivers/net/foo.c depends only on the CONFIG_* lines that
-    it actually uses.
-
-    A new program, split-include.c, runs at the beginning of
-    compilation (make bzImage or make zImage).  split-include reads
-    include/linux/autoconf.h and updates the include/config/ tree,
-    writing one file per option.  It updates only the files for options
-    that have changed.
-
-Flag Dependencies
-
-    Martin Von Loewis contributed another feature to this patch:
-    'flag dependencies'.  The idea is that a .o file depends on
-    the compilation flags used to build it.  The file foo.o has
-    its flags stored in .flags.foo.o.
-
-    Suppose the user changes the foo driver from resident to modular.
-    'make' will notice that the current foo.o was not compiled with
-    -DMODULE and will recompile foo.c.
-
-    All .o files made from C source have flag dependencies.  So do .o
-    files made with ld, and .a files made with ar.  However, .o files
-    made from assembly source do not have flag dependencies (nobody
-    needs this yet, but it would be good to fix).
-
-Per-source-file Flags
-
-    Flag dependencies also work with per-source-file flags.
-    You can specify compilation flags for individual source files
-    like this:
-
-	CFLAGS_foo.o = -DSPECIAL_FOO_DEFINE
-
-    This helps clean up drivers/net/Makefile, drivers/scsi/Makefile,
-    and several other Makefiles.
-
-Credit
-
-    Werner Almesberger had the original idea and wrote the first
-    version of this patch.
-    
-    Michael Chastain picked it up and continued development.  He is
-    now the principal author and maintainer.  Please report any bugs
-    to him.
-
-    Martin von Loewis wrote flag dependencies, with some modifications
-    by Michael Chastain.
-
-    Thanks to all of the beta testers.