Modernize toolchain script and add generic arm toolchain

I did some cleanup of redudant stuff, simplify some logic, also switch to bash
because sh in the pain when ones want to locally define variables for functions
calls. I also added support to download more stuff like alsa-lib and more recent
gccs that use a different naming convention, as well as linux kernels.

I also add some build to build linux toolchains without ct-ng. The biggest problem
with ct-ng is that they regularly drop support for old stuff and as a result it
rots really quickly for old toolchains. I add a new toolchain for generic linux arm
with the minimum requirements, it works fine on Sony NWZ and also on YP-R0.

Finally, rockboxdev.sh now understand options on its command line (see --help).
Notably --target to give the list of targets (useful for noninteractive scripts),
--restart to restart at a step, --makeflags and others (instead of the environment
variables)

Change-Id: I869760c1faeb00ab381796a4cda82ffbc9637123

1 files changed, 476 insertions, 80 deletions

diff --git a/tools/rockboxdev.sh b/tools/rockboxdev.sh
index 5f9d1acbac..55efe94308 100755
--- a/tools/rockboxdev.sh
+++ b/tools/rockboxdev.sh
@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/bin/bash
 
 # Abort execution as soon as an error is encountered
 # That way the script do not let the user think the process completed correctly
@@ -33,6 +33,10 @@ if [ -z $GNU_MIRROR ] ; then
     GNU_MIRROR=http://mirrors.kernel.org/gnu
 fi
 
+if [ -z $LINUX_MIRROR ] ; then
+    LINUX_MIRROR=http://www.kernel.org/pub/linux
+fi
+
 # These are the tools this script requires and depends upon.
 reqtools="gcc bzip2 gzip make patch makeinfo automake libtool autoconf flex bison"
 
@@ -53,77 +57,291 @@ findtool(){
   done
 }
 
+findlib (){
+    lib="$1"
+    # on error, gcc will spit out "cannot find -lxxxx", but it may not be in
+    # english so grep for -lxxxx
+    if ! gcc -l$lib 2>&1 | grep -q -- "-l$lib"; then
+        echo "ok"
+        return
+    fi
+}
+
+# check if all the libraries in argument are installed, exit with error if not
+checklib() {
+    for t in "$@"; do
+        lib=`findlib $t`
+        if test -z "$lib"; then
+            echo "ROCKBOXDEV: library \"$t\" is required for this script to work."
+            missingtools="yes"
+        fi
+    done
+    if [ -n "$missingtools" ]; then
+        echo "ROCKBOXDEV: Please install the missing libraries and re-run the script."
+        exit 1
+    fi
+}
+
 input() {
     read response
     echo $response
 }
 
-#$1 file
-#$2 URL"root
-getfile() {
-  if test -f $dlwhere/$1; then
-    echo "ROCKBOXDEV: Skipping download of $2/$1: File already exists"
-    return
-  fi
-  tool=`findtool curl`
-  if test -z "$tool"; then
-    tool=`findtool wget`
-    if test -n "$tool"; then
-      # wget download
-      echo "ROCKBOXDEV: Downloading $2/$1 using wget"
-      $tool -T 60 -O $dlwhere/$1 $2/$1
+# compare two versions, return 1 if first version is strictly before the second
+# version_lt ver1 ver2
+version_lt() {
+    # use sort with natural version sorting
+    ltver=`printf "$1\n$2" | sort -V | head -n 1`
+    [ "$1" = "$ltver" ] && true || false
+}
+
+# Download a file from a server (unless it already exists locally in $dlwhere).
+# The output file name is always $dlwhere/$1, and the function will try URLs
+# one after the other
+# $1 file
+# $2 server file name
+# $2,$3,... URL root list
+getfile_ex() {
+    out_file="$dlwhere/$1"
+    srv_file="$2"
+    if test -f $out_file; then
+        echo "ROCKBOXDEV: Skipping download of $1: File already exists"
+        return
+    fi
+    # find tool (curl or wget) and build download command
+    tool=`findtool curl`
+    if test -z "$tool"; then
+        tool=`findtool wget`
+        if test -n "$tool"; then
+            # wget download
+            echo "ROCKBOXDEV: Downloading $1 using wget"
+            tool="$tool -T 60 -O "
+        else
+            echo "ROCKBOXDEV: No downloader tool found!"
+            echo "ROCKBOXDEV: Please install curl or wget and re-run the script"
+            exit
+        fi
+    else
+        # curl download
+        echo "ROCKBOXDEV: Downloading $1 using curl"
+        tool="$tool -fLo "
     fi
-  else
-     # curl download
-      echo "ROCKBOXDEV: Downloading $2/$1 using curl"
-     $tool -Lo $dlwhere/$1 $2/$1
-  fi
 
-  if [ $? -ne 0 ] ; then
-      echo "ROCKBOXDEV: couldn't download the file!"
-      echo "ROCKBOXDEV: check your internet connection"
-      exit
-  fi
+    # shift arguments so that $@ is the list of URLs
+    shift
+    shift
+    for url in "$@"; do
+        echo "ROCKBOXDEV: try $url/$srv_file"
+        if $tool "$out_file" "$url/$srv_file"; then
+            return
+        fi
+    done
 
-  if test -z "$tool"; then 
-    echo "ROCKBOXDEV: No downloader tool found!"
-    echo "ROCKBOXDEV: Please install curl or wget and re-run the script"
+    echo "ROCKBOXDEV: couldn't download the file!"
+    echo "ROCKBOXDEV: check your internet connection"
     exit
-  fi
 }
 
+#$1 file
+#$2 URL"root
+# Output file name is the same as the server file name ($1)
+# Does not download the file if it already exists locally in $dlwhere/
+getfile() {
+    getfile_ex "$1" "$1" "$2"
+}
 
-build() {
+# wrapper around getfile to abstract url
+# getttool tool version
+# the file is always downloaded to "$dlwhere/$toolname-$version.tar.bz2"
+gettool() {
     toolname="$1"
-    target="$2"
-    version="$3"
-    patch="$4"
-    configure_params="$5"
-    needs_libs="$6"
-
-    patch_url="http://www.rockbox.org/gcc"
-
+    version="$2"
+    ext="tar.bz2"
+    file="$toolname-$version"
+    srv_file="$toolname-$version"
     case $toolname in
         gcc)
-            file="gcc-core-$version.tar.bz2"
+            # before 4.7, the tarball was named gcc-core
+            if version_lt "$version" "4.7"; then
+                srv_file="gcc-core-$version"
+            fi
             url="$GNU_MIRROR/gcc/gcc-$version"
             ;;
 
         binutils)
-            file="binutils-$version.tar.bz2"
             url="$GNU_MIRROR/binutils"
             ;;
 
+        glibc)
+            url="$GNU_MIRROR/glibc"
+            ;;
+
         crosstool-ng)
-            file="crosstool-ng-$version.tar.bz2"
             url="http://crosstool-ng.org/download/crosstool-ng"
             ;;
+
+        alsa-lib)
+            url="ftp://ftp.alsa-project.org/pub/lib/"
+            ;;
+
+        linux)
+            # FIXME linux kernel server uses an overcomplicated architecture,
+            # especially for longterm kernels, so we need to lookup several
+            # places. This will need fixing for non-4-part 2.6 versions but it
+            # is written in a way that should make it easy
+            case "$version" in
+                2.6.*.*)
+                    # 4-part versions -> remove last digit for longterm
+                    longterm_ver="${version%.*}"
+                    top_dir="v2.6"
+                    ;;
+
+                *)
+                    echo "ROCKBOXDEV: I don't know how to handle this kernel version: $version"
+                    exit
+                ;;
+            esac
+            base_url="http://www.kernel.org/pub/linux/kernel/$top_dir"
+            url="$base_url $base_url/longterm/v$longterm_ver $base_url/longterm"
+            ext="tar.gz"
+            ;;
+
         *)
             echo "ROCKBOXDEV: Bad toolname $toolname"
             exit
             ;;
     esac
-    
+    getfile_ex "$file.$ext" "$srv_file.$ext" $url
+}
+
+# extract file to the current directory
+# extract file
+extract() {
+    if [ -d "$1" ]; then
+        echo "ROCKBOXDEV: Skipping extraction of $1: already done"
+        return
+    fi
+    echo "ROCKBOXDEV: extracting $1"
+    if [ -f "$dlwhere/$1.tar.bz2" ]; then
+        tar xjf "$dlwhere/$1.tar.bz2"
+    elif [ -f "$dlwhere/$1.tar.gz" ]; then
+        tar xzf "$dlwhere/$1.tar.gz"
+    else
+        echo "ROCKBOXDEV: I don't know how to extract $1 (no bzip2 or gzip)"
+        exit
+    fi
+}
+
+# run a command, and a log command and output to a file (append)
+# exit on error
+# run_cmd logfile cmd...
+run_cmd() {
+    logfile="$1"
+    shift
+    echo "Running '$@'" >>$logfile
+    if ! $@ >> "$logfile" 2>&1; then
+        echo "ROCKBOXDEV: an error occured, please see $logfile"
+        exit
+    fi
+}
+
+# check if the following should be executed or not, depending on RESTART variable:
+# $1=tool
+# If RESTART is empty, always perform step, otherwise only perform is there is
+# an exact match. On the first match, RESTART is reset to "" so that next step
+# are executed
+check_restart() {
+    if [ "$1" = "$RESTART" ]; then
+        RESTART=""
+        true
+    fi
+    [ "$RESTART" = "" ] && true || false
+}
+
+# advanced tool building: create a build directory, run configure, run make
+# and run make install. It is possible to customize all steps or disable them
+# $1=tool
+# $2=version
+# $3=configure options, or "NO_CONFIGURE" to disable step
+# $4=make options, or "NO_MAKE" to disable step
+# $5=make install options (will be replaced by "install" if left empty)
+# By default, the restary step is the toolname, but it can be changed by setting
+# RESTART_STEP
+buildtool() {
+    tool="$1"
+    version="$2"
+    toolname="$tool-$version"
+    config_opt="$3"
+    make_opts="$4"
+    install_opts="$5"
+    logfile="$builddir/build-$toolname.log"
+
+    stepname=${RESTART_STEP-$tool}
+    if ! check_restart "$stepname"; then
+        echo "ROCKBOXDEV: Skipping step '$stepname' as requested per RESTART"
+        return
+    fi
+    echo "ROCKBOXDEV: Starting step '$stepname'"
+
+    echo "ROCKBOXDEV: logging to $logfile"
+    rm -f "$logfile"
+
+    echo "ROCKBOXDEV: mkdir build-$toolname"
+    mkdir "build-$toolname"
+
+    echo "ROCKBOXDEV: cd build-$toolname"
+    cd "build-$toolname"
+
+    # in-tree/out-of-tree build
+    case "$tool" in
+        linux|alsa-lib)
+            # in-intree
+            echo "ROCKBOXDEV: copy $toolname for in-tree build"
+            # copy the source directory to the build directory
+            cp -r ../$toolname/* .
+            cfg_dir="."
+            ;;
+
+        *)
+            # out-of-tree
+            cfg_dir="../$toolname";
+            ;;
+    esac
+
+    if [ "$config_opt" != "NO_CONFIGURE" ]; then
+        echo "ROCKBOXDEV: $toolname/configure"
+        # NOTE glibc requires to be compiled with optimization
+        CFLAGS='-U_FORTIFY_SOURCE -fgnu89-inline -O2' run_cmd "$logfile" \
+            "$cfg_dir/configure" "--prefix=$prefix" \
+            --disable-docs $config_opt
+    fi
+
+    if [ "$make_opts" != "NO_MAKE" ]; then
+        echo "ROCKBOXDEV: $toolname/make"
+        run_cmd "$logfile" $make $make_opts
+    fi
+
+    if [ "$install_opts" = "" ]; then
+        install_opts="install"
+    fi
+    echo "ROCKBOXDEV: $toolname/make (install)"
+    run_cmd "$logfile" $make $install_opts
+
+    echo "ROCKBOXDEV: rm -rf build-$toolname $toolname"
+    cd ..
+    rm -rf build-$toolname
+}
+
+build() {
+    toolname="$1"
+    target="$2"
+    version="$3"
+    patch="$4"
+    configure_params="$5"
+    needs_libs="$6"
+
+    patch_url="http://www.rockbox.org/gcc"
+
     # create build directory
     if test -d $builddir; then
         if test ! -w $builddir; then
@@ -135,21 +353,17 @@ build() {
     fi
 
     # download source tarball
-    if test ! -f "$dlwhere/$file"; then
-        getfile "$file" "$url"
-    fi
+    gettool "$toolname" "$version"
+    file="$toolname-$version"
 
     # download patch
     for p in $patch; do
-        if test ! -f "$dlwhere/$p"; then
-            getfile "$p" "$patch_url"
-        fi
+        getfile "$p" "$patch_url"
     done
 
     cd $builddir
 
-    echo "ROCKBOXDEV: extracting $file"
-    tar xjf $dlwhere/$file
+    extract "$toolname-$version"
 
     # do we have a patch?
     for p in $patch; do
@@ -170,27 +384,21 @@ build() {
         cd "gcc-$version"
         if (echo $needs_libs | grep -q gmp && test ! -d gmp); then
             echo "ROCKBOXDEV: Getting GMP"
-            if test ! -f $dlwhere/gmp-4.3.2.tar.bz2; then
-                getfile "gmp-4.3.2.tar.bz2" "$GNU_MIRROR/gmp"
-            fi
+            getfile "gmp-4.3.2.tar.bz2" "$GNU_MIRROR/gmp"
             tar xjf $dlwhere/gmp-4.3.2.tar.bz2
             ln -s gmp-4.3.2 gmp
         fi
 
         if (echo $needs_libs | grep -q mpfr && test ! -d mpfr); then
             echo "ROCKBOXDEV: Getting MPFR"
-            if test ! -f $dlwhere/mpfr-2.4.2.tar.bz2; then
-                getfile "mpfr-2.4.2.tar.bz2" "$GNU_MIRROR/mpfr"
-            fi
+            getfile "mpfr-2.4.2.tar.bz2" "$GNU_MIRROR/mpfr"
             tar xjf $dlwhere/mpfr-2.4.2.tar.bz2
             ln -s mpfr-2.4.2 mpfr
         fi
 
         if (echo $needs_libs | grep -q mpc && test ! -d mpc); then
             echo "ROCKBOXDEV: Getting MPC"
-            if test ! -f $dlwhere/mpc-0.8.1.tar.gz; then
-                getfile "mpc-0.8.1.tar.gz" "http://www.multiprecision.org/mpc/download"
-            fi
+            getfile "mpc-0.8.1.tar.gz" "http://www.multiprecision.org/mpc/download"
             tar xzf $dlwhere/mpc-0.8.1.tar.gz
             ln -s mpc-0.8.1 mpc
         fi
@@ -226,7 +434,6 @@ build() {
     rm -rf build-$toolname $toolname-$version
 }
 
-
 make_ctng() {
     if test -f "`which ct-ng 2>/dev/null`"; then
         ctng="ct-ng"
@@ -288,25 +495,170 @@ build_ctng() {
     cd $builddir
     rm -rf $builddir/build-$ctng_target
 }
-    
+
+# build a cross compiler toolchain for linux
+# $1=target
+# $2=binutils version
+# $3=binutils configure extra options
+# $4=gcc version
+# $5=gcc configure extra options
+# $6=linux version
+# $7=glibc version
+# $8=glibc configure extra options
+build_linux_toolchain () {
+    target="$1"
+    binutils_ver="$2"
+    binutils_opts="$3"
+    gcc_ver="$4"
+    gcc_opts="$5"
+    linux_ver="$6"
+    glibc_ver="$7"
+    glibc_opts="$8"
+    # where to put the sysroot
+    sysroot="$prefix/$target/sysroot"
+    # extract arch from target
+    arch=${target%%-*}
+
+    # check libraries:
+    # contrary to other toolchains that rely on a hack to avoid installing
+    # gmp, mpc and mpfr, we simply require that they are installed on the system
+    # this is not a huge requirement since virtually all systems these days
+    # provide dev packages for them
+    # FIXME: maybe add an option to download and install them automatically
+    checklib "mpc" "gmp" "mpfr"
+
+    # create build directory
+    if test -d $builddir; then
+        if test ! -w $builddir; then
+            echo "ROCKBOXDEV: No write permission for $builddir"
+            exit
+        fi
+    else
+        mkdir -p $builddir
+    fi
+
+    # download all tools
+    gettool "binutils" "$binutils_ver"
+    gettool "gcc" "$gcc_ver"
+    gettool "linux" "$linux_ver"
+    gettool "glibc" "$glibc_ver"
+
+    # extract them
+    cd $builddir
+    extract "binutils-$binutils_ver"
+    extract "gcc-$gcc_ver"
+    extract "linux-$linux_ver"
+    extract "glibc-$glibc_ver"
+
+    # we make it possible to restart a build on error by using the RESTART
+    # variable, the format is RESTART="tool" where tool is the toolname at which
+    # to restart (binutils, gcc)
+
+    # install binutils, with support for sysroot
+    buildtool "binutils" "$binutils_ver" "--target=$target --disable-werror \
+        --with-sysroot=$sysroot --disable-nls" "" ""
+    # build stage 1 compiler: disable headers, disable threading so that
+    # pthread headers are not included, pretend we use newlib so that libgcc
+    # doesn't get linked at the end
+    # NOTE there is some magic involved here
+    RESTART_STEP="gcc-stage1" \
+    buildtool "gcc" "$gcc_ver" "$gcc_opts --enable-languages=c --target=$target \
+        --without-headers --disable-threads --disable-libgomp --disable-libmudflap \
+        --disable-libssp --disable-libquadmath --disable-libquadmath-support \
+        --disable-shared --with-newlib --disable-libitm \
+        --disable-libsanitizer --disable-libatomic" "" ""
+    # install linux headers
+    # NOTE: we need to tell make where to put the build files, since buildtool
+    # switches to the builddir, "." will be the correct builddir when ran
+    linux_opts="O=. ARCH=$arch INSTALL_HDR_PATH=$sysroot/usr/"
+    RESTART_STEP="linux-headers" \
+    buildtool "linux" "$linux_ver" "NO_CONFIGURE" \
+        "$linux_opts headers_install" "$linux_opts headers_check"
+    # build glibc using the first stage cross compiler
+    # we need to set the prefix to /usr because the glibc runs on the actual
+    # target and is indeed installed in /usr
+    prefix="/usr" \
+    buildtool "glibc" "$glibc_ver" "--target=$target --host=$target --build=$MACHTYPE \
+        --with-__thread --with-headers=$sysroot/usr/include $glibc_opts" \
+        "" "install install_root=$sysroot"
+    # build stage 2 compiler
+    buildtool "gcc" "$gcc_ver" "$gcc_opts --enable-languages=c,c++ --target=$target \
+        --with-sysroot=$sysroot" "" ""
+}
+
+usage () {
+    echo "usage: rockboxdev.sh [options]"
+    echo "options:"
+    echo "  --help              Display this help"
+    echo "  --target=LIST       List of targets to build"
+    echo "  --restart=STEP      Restart build at given STEP (same as RESTART env var)"
+    echo "  --prefix=PREFIX     Set install prefix (same as RBDEV_PREFIX env var)"
+    echo "  --dlwhere=DIR       Set download directory (same as RBDEV_DOWNLOAD env var)"
+    echo "  --builddir=DIR      Set build directory (same as RBDEV_BUILD env var)"
+    echo "  --makeflags=FLAGS   Set make flags (same as MAKEFLAGS env var)"
+    exit 1
+}
+
 ##############################################################################
 # Code:
 
-# Verify required tools
+# Parse arguments
+for i in "$@"
+do
+case $i in
+    --help)
+        usage
+        ;;
+    --prefix=*)
+        prefix="${i#*=}"
+        shift
+        ;;
+    --target=*)
+        RBDEV_TARGET="${i#*=}"
+        shift
+        ;;
+    --restart=*)
+        RBDEV_RESTART="${i#*=}"
+        shift
+        ;;
+    --dlwhere=*)
+        dlwhere="${i#*=}"
+        shift
+        ;;
+    --builddir=*)
+        builddir="${i#*=}"
+        shift
+        ;;
+    --makeflags=*)
+        export MAKEFLAGS="${i#*=}" # export so it's available in make
+        shift
+        ;;
+    *)
+        echo "Unknown option '$i'"
+        exit 1
+        ;;
+esac
+done
+
+# Verify required tools and libraries
 for t in $reqtools; do
     tool=`findtool $t`
     if test -z "$tool"; then
         echo "ROCKBOXDEV: \"$t\" is required for this script to work."
-        echo "ROCKBOXDEV: Please install \"$t\" and re-run the script."
-        exit
+        missingtools="yes"
     fi
 done
+if [ -n "$missingtools" ]; then
+    echo "ROCKBOXDEV: Please install the missing tools and re-run the script."
+    exit 1
+fi
 
-echo "Download directory : $dlwhere (set RBDEV_DOWNLOAD to change)"
-echo "Install prefix     : $prefix  (set RBDEV_PREFIX to change)"
-echo "Build dir          : $builddir (set RBDEV_BUILD to change)"
-echo "Make options       : $MAKEFLAGS (set MAKEFLAGS to change)"
-echo ""
+echo "Download directory : $dlwhere (set RBDEV_DOWNLOAD or use --download= to change)"
+echo "Install prefix     : $prefix  (set RBDEV_PREFIX or use --prefix= to change)"
+echo "Build dir          : $builddir (set RBDEV_BUILD or use --builddir= to change)"
+echo "Make options       : $MAKEFLAGS (set MAKEFLAGS or use --makeflags= to change)"
+echo "Restart step       : $RBDEV_RESTART (set RBDEV_RESTART or use --restart= to change)"
+echo "Target arch        : $RBDEV_TARGET (set RBDEV_TARGET or use --target to change)"
 
 # Verify download directory
 if test -d "$dlwhere"; then
@@ -336,17 +688,21 @@ if test ! -w $prefix; then
   exit
 fi
 
-echo "Select target arch:"
-echo "s   - sh       (Archos models)"
-echo "m   - m68k     (iriver h1x0/h3x0, iaudio m3/m5/x5 and mpio hd200)"
-echo "a   - arm      (ipods, iriver H10, Sansa, D2, Gigabeat, etc)"
-echo "i   - mips     (Jz4740 and ATJ-based players)"
-echo "r   - arm-app  (Samsung ypr0)"
-echo "separate multiple targets with spaces"
-echo "(Example: \"s m a\" will build sh, m68k and arm)"
-echo ""
-
-selarch=`input`
+if [ -z "$RBDEV_TARGET" ]; then
+    echo "Select target arch:"
+    echo "s   - sh       (Archos models)"
+    echo "m   - m68k     (iriver h1x0/h3x0, iaudio m3/m5/x5 and mpio hd200)"
+    echo "a   - arm      (ipods, iriver H10, Sansa, D2, Gigabeat, etc)"
+    echo "i   - mips     (Jz4740 and ATJ-based players)"
+    echo "r   - arm-app  (Samsung ypr0)"
+    echo "x   - arm-linux  (Generic Linux ARM: Samsung ypr0, Linux-based Sony NWZ)"
+    echo "separate multiple targets with spaces"
+    echo "(Example: \"s m a\" will build sh, m68k and arm)"
+    echo ""
+    selarch=`input`
+else
+    selarch=$RBDEV_TARGET
+fi
 system=`uname -s`
 
 # add target dir to path to ensure the new binutils are used in gcc build
@@ -394,6 +750,46 @@ do
         [Rr])
             build_ctng "ypr0" "alsalib.tar.gz" "arm" "linux-gnueabi"
             ;;
+        [Xx])
+            # IMPORTANT NOTE
+            # This toolchain must support several targets and thus must support
+            # the oldest possible configuration.
+            #
+            # Samsung YP-R0/R1:
+            #  ARM1176JZF-S, softfp EABI
+            #   gcc: 4.9.4 is the latest 4.9.x stable branch, also the only one that
+            #        compiles with GCC >6
+            #   kernel: 2.6.27.59 is the same 2.6.x stable kernel as used by the
+            #           original ct-ng toolchain, the device runs kernel 2.6.24
+            #   glibc: 2.19 is the latest version that supports kernel 2.6.24 which
+            #          is used on the device, but we need to support ABI 2.4 because
+            #          the device uses glibc 2.4.2
+            #
+            # Sony NWZ:
+            #   gcc: 4.9.4 is the latest 4.9.x stable branch, also the only one that
+            #        compiles with GCC >6
+            #   kernel: 2.6.32.68 is the latest 2.6.x stable kernel, the device
+            #           runs kernel 2.6.23 or 2.6.35 or 3.x for the most recent
+            #   glibc: 2.19 is the latest version that supports kernel 2.6.23 which
+            #          is used on many Sony players, but we need to support ABI 2.7
+            #          because the device uses glibc 2.7
+            #
+            # Thus the lowest common denominator is to use the latest 2.6.x stable
+            # kernel but compile glibc to support kernel 2.6.23 and glibc 2.4.
+            # We use a recent 2.26.1 binutils to avoid any build problems and
+            # avoid patches/bugs.
+            glibcopts="--enable-kernel=2.6.23 --enable-oldest-abi=2.4"
+            build_linux_toolchain "arm-rockbox-linux-gnueabi" "2.26.1" "" "4.9.4" \
+                "$gccopts" "2.6.32.68" "2.19" "$glibcopts"
+            # build alsa-lib
+            # we need to set the prefix to how it is on device (/usr) and then
+            # tweak install dir at make install step
+            alsalib_ver="1.0.19"
+            gettool "alsa-lib" "$alsalib_ver"
+            extract "alsa-lib-$alsalib_ver"
+            prefix="/usr" buildtool "alsa-lib" "$alsalib_ver" \
+                "--host=$target --disable-python" "" "install DESTDIR=$prefix/$target/sysroot"
+            ;;
         *)
             echo "ROCKBOXDEV: Unsupported architecture option: $arch"
             exit