[PATCH] config: update usage/help info

Replace outdated help message with a reference to README. Update README
for make *config variants and environment variable info.

Signed-off-by: Randy Dunlap <[e-mail]>
Acked-by: Sam Ravnborg <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

README

···
 	"make xconfig"     X windows (Qt) based configuration tool.
 	"make gconfig"     X windows (Gtk) based configuration tool.
 	"make oldconfig"   Default all questions based on the contents of
-			   your existing ./.config file.
+			   your existing ./.config file and asking about
+			   new config symbols.
 	"make silentoldconfig"
 			   Like above, but avoids cluttering the screen
 			   with questions already answered.
+	"make defconfig"   Create a ./.config file by using the default
+			   symbol values from arch/$ARCH/defconfig.
+	"make allyesconfig"
+			   Create a ./.config file by setting symbol
+			   values to 'y' as much as possible.
+	"make allmodconfig"
+			   Create a ./.config file by setting symbol
+			   values to 'm' as much as possible.
+	"make allnoconfig" Create a ./.config file by setting symbol
+			   values to 'n' as much as possible.
+	"make randconfig"  Create a ./.config file by setting symbol
+			   values to random values.
+
+   The allyesconfig/allmodconfig/allnoconfig/randconfig variants can
+   also use the environment variable KCONFIG_ALLCONFIG to specify a
+   filename that contains config options that the user requires to be
+   set to a specific value.  If KCONFIG_ALLCONFIG=filename is not used,
+   "make *config" checks for a file named "all{yes/mod/no/random}.config"
+   for symbol values that are to be forced.  If this file is not found,
+   it checks for a file named "all.config" to contain forced values.
    
 	NOTES on "make config":
 	- having unnecessary drivers will make the kernel bigger, and can

scripts/kconfig/conf.c

···
 
 #include <ctype.h>
 #include <stdlib.h>
+#include <stdio.h>
 #include <string.h>
 #include <unistd.h>
 #include <time.h>
···
 			break;
 		case 'h':
 		case '?':
-			printf("%s [-o|-s] config\n", av[0]);
+			fprintf(stderr, "See README for usage info\n");
 			exit(0);
 		}
 	}