scripts: add miniconfig.sh to aid in mini.config creation

Signed-off-by: Phil Sutter <phil@nwl.cc>

scripts/miniconfig.sh

@@ -0,0 +1,50 @@
+#!/bin/sh
+
+# miniconfig.sh copyright 2005 by Rob Landley <rob@landley.net>
+# Licensed under the GNU General Public License version 2.
+#
+# This script aids in building a mini.config from a fully fledged kernel
+# config. To do so, change into the kernel source directory and call this
+# script with the full config as first parameter. The output will be written to
+# a file named 'mini.config' in the same directory.
+#
+# Beware: This runs for a long time and the output might not be optimal. When
+# using it, bring some beer but don't drink too much so you're still able to
+# manually review the output in the end.
+
+if [ $# -ne 1 ] || [ ! -f "$1" ]; then
+	echo "Usage: miniconfig.sh configfile"
+	exit 1
+fi
+
+if [ "$1" == ".config" ]; then
+	echo "It overwrites .config, rename it and try again."
+	exit 1
+fi
+
+cp $1 mini.config
+echo "Calculating mini.config..."
+
+LENGTH=`cat $1 | wc -l`
+
+# Loop through all lines in the file
+I=1
+while true; do
+	if [ $I -gt $LENGTH ]; then
+		exit
+	fi
+	sed -n "${I}!p" mini.config > .config.test
+	# Do a config with this file
+	make allnoconfig KCONFIG_ALLCONFIG=.config.test > /dev/null
+
+	# Compare.  The date changes so expect a small difference each time.
+	D=`diff .config $1 | wc -l`
+	if [ $D -eq 4 ]; then
+		mv .config.test mini.config
+		LENGTH=$[$LENGTH-1]
+	else
+		I=$[$I + 1]
+	fi
+	echo -n -e $I/$LENGTH lines `cat mini.config | wc -c` bytes "\r"
+done
+echo