[PATCH] kbuild: permanently fix kernel configuration include mess

Include autoconf.h into every kernel compilation via the gcc command line
using -imacros.  This ensures that we have the kernel configuration
included from the start, rather than relying on each file having #include
<linux/config.h> as appropriate.  History has shown that this is something
which is difficult to get right.

Since we now include the kernel configuration automatically, make
configcheck becomes meaningless, so remove it.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>

Makefile

@@ -346,7 +346,8 @@ AFLAGS_KERNEL	=
 # Use LINUXINCLUDE when you must reference the include/ directory.
 # Needed to be compatible with the O= option
 LINUXINCLUDE    := -Iinclude \
-                   $(if $(KBUILD_SRC),-Iinclude2 -I$(srctree)/include)
+                   $(if $(KBUILD_SRC),-Iinclude2 -I$(srctree)/include) \
+		   -imacros include/linux/autoconf.h
 
 CPPFLAGS        := -D__KERNEL__ $(LINUXINCLUDE)
 
@@ -1249,11 +1250,6 @@ tags: FORCE
 # Scripts to check various things for consistency
 # ---------------------------------------------------------------------------
 
-configcheck:
-	find * $(RCS_FIND_IGNORE) \
-		-name '*.[hcS]' -type f -print | sort \
-		| xargs $(PERL) -w scripts/checkconfig.pl
-
 includecheck:
 	find * $(RCS_FIND_IGNORE) \
 		-name '*.[hcS]' -type f -print | sort \

include/linux/config.h

 #ifndef _LINUX_CONFIG_H
 #define _LINUX_CONFIG_H
-
+/* This file is no longer in use and kept only for backward compatibility.
+ * autoconf.h is now included via -imacros on the commandline
+ */
 #include <linux/autoconf.h>
 
 #endif