Update to rscons 2.3.0

Move cross compiler to i686-elf-gcc directory.
Automatically build cross compiler using rscons subsidiary script.

i686-elf-gcc/Rsconscript

@@ -0,0 +1,17 @@
+configure do
+  check_c_compiler "gcc"
+  check_program "make"
+  check_program "bison"
+  check_program "flex"
+  check_program "texi2any", on_fail: "Install the texinfo package"
+  check_program "wget"
+  check_lib "gmp", on_fail: "Install the libgmp-dev package"
+  check_lib "mpc", on_fail: "Install the libmpc-dev package"
+  check_lib "mpfr", on_fail: "Install the libmpfr-dev package"
+end
+
+build do
+  unless File.exist?("i686-elf-gcc")
+    system("./build.sh")
+  end
+end

i686-elf-gcc/build.sh

@@ -0,0 +1,64 @@
+#!/bin/bash
+
+BINUTILS_VERSION="2.35"
+BINUTILS_CHECKSUM="1b11659fb49e20e18db460d44485f09442c8c56d5df165de9461eb09c8302f85"
+GCC_VERSION="10.2.0"
+GCC_CHECKSUM="b8dd4368bb9c7f0b98188317ee0254dd8cc99d1e3a18d0ff146c855fe16c1d8c"
+
+if [ ! -e binutils-${BINUTILS_VERSION}.tar.xz ]; then
+  wget -O binutils-${BINUTILS_VERSION}.tar.xz https://ftp.gnu.org/gnu/binutils/binutils-${BINUTILS_VERSION}.tar.xz
+fi
+
+if [[ ! `sha256sum binutils-${BINUTILS_VERSION}.tar.xz` =~ $BINUTILS_CHECKSUM ]]; then
+  echo "Invalid binutils-${BINUTILS_VERSION}.tar.xz checksum"
+  exit
+fi
+
+if [ ! -d binutils-${BINUTILS_VERSION} ]; then
+  tar xJf binutils-${BINUTILS_VERSION}.tar.xz
+fi
+
+if [ ! -e gcc-${GCC_VERSION}.tar.xz ]; then
+  wget -O gcc-${GCC_VERSION}.tar.xz https://ftp.gnu.org/gnu/gcc/gcc-${GCC_VERSION}/gcc-${GCC_VERSION}.tar.xz
+fi
+
+if [[ ! `sha256sum gcc-${GCC_VERSION}.tar.xz` =~ $GCC_CHECKSUM ]]; then
+  echo "Invalid gcc-${GCC_VERSION}.tar.xz checksum"
+  exit
+fi
+
+if [ ! -d gcc-${GCC_VERSION} ]; then
+  tar xJf gcc-${GCC_VERSION}.tar.xz
+fi
+
+export PREFIX="$PWD/i686-elf-gcc"
+export TARGET="i686-elf"
+export PATH="$PREFIX/bin:$PATH"
+
+function build_binutils()
+{
+  rm -rf build-binutils
+  mkdir -p build-binutils
+  (
+    cd build-binutils
+    ../binutils-${BINUTILS_VERSION}/configure --target="$TARGET" --prefix="$PREFIX" --with-sysroot --disable-nls --disable-werror && \
+    make && \
+    make install
+  )
+}
+
+function build_gcc()
+{
+  rm -rf build-gcc
+  mkdir -p build-gcc
+  (
+    cd build-gcc
+    ../gcc-${GCC_VERSION}/configure --target="$TARGET" --prefix="$PREFIX" --disable-nls --enable-languages=c,c++ --without-headers && \
+    make all-gcc && \
+    make all-target-libgcc && \
+    make install-gcc && \
+    make install-target-libgcc
+  )
+}
+
+build_binutils && build_gcc

i686-elf-gcc/clean.sh

@@ -0,0 +1,2 @@
+#!/bin/sh
+rm -rf build build-* binutils* gcc-*

i686-elf-gcc/configure

@@ -0,0 +1,2 @@
+#!/bin/sh
+exec ../rscons configure