package: add generic support for lz archives

This commit teaches the generic package handling code how to extract .tar.lz
archives. When lzip is not installed on the host, host-lzip gets built
automatically.

Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Reviewed-by: Thomas De Schampheleire <thomas.de_schampheleire@nokia.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

Config.in

@@ -158,6 +158,13 @@ config BR2_XZCAT
 	  Command to be used to extract a xz'ed file to stdout.
 	  Default is "xzcat"
 
+config BR2_LZCAT
+	string "lzcat command"
+	default "lzip -d -c"
+	help
+	  Command to be used to extract a lzip'ed file to stdout.
+	  Default is "lzip -d -c"
+
 config BR2_TAR_OPTIONS
 	string "Tar options"
 	default ""

Makefile

@@ -432,6 +432,7 @@ KERNEL_ARCH := $(shell echo "$(ARCH)" | sed -e "s/-.*//" \
 ZCAT := $(call qstrip,$(BR2_ZCAT))
 BZCAT := $(call qstrip,$(BR2_BZCAT))
 XZCAT := $(call qstrip,$(BR2_XZCAT))
+LZCAT := $(call qstrip,$(BR2_LZCAT))
 TAR_OPTIONS = $(call qstrip,$(BR2_TAR_OPTIONS)) -xf
 
 # packages compiled for the host go here

package/pkg-utils.mk

@@ -36,6 +36,7 @@ pkgname = $(lastword $(subst /, ,$(pkgdir)))
 # Define extractors for different archive suffixes
 INFLATE.bz2  = $(BZCAT)
 INFLATE.gz   = $(ZCAT)
+INFLATE.lz   = $(LZCAT)
 INFLATE.lzma = $(XZCAT)
 INFLATE.tbz  = $(BZCAT)
 INFLATE.tbz2 = $(BZCAT)

support/dependencies/check-host-lzip.mk

@@ -0,0 +1,5 @@
+ifeq (,$(call suitable-host-package,lzip,$(LZCAT)))
+DEPENDENCIES_HOST_PREREQ += host-lzip
+EXTRACTOR_DEPENDENCY_PRECHECKED_EXTENSIONS += .lz
+LZCAT = $(HOST_DIR)/usr/bin/lzip -d -c
+endif

support/dependencies/check-host-lzip.sh

@@ -0,0 +1,14 @@
+#!/bin/sh
+
+candidate="$1"
+
+lzip=`which $candidate 2>/dev/null`
+if [ ! -x "$lzip" ]; then
+	lzip=`which lzip 2>/dev/null`
+	if [ ! -x "$lzip" ]; then
+		# echo nothing: no suitable lzip found
+		exit 1
+	fi
+fi
+
+echo $lzip