Added cross compiler script at @uberhacker's request (#2544)

* Added cross compiler script at @uberhacker's request

* Disabled libmpx, adds lines to save space

tools/build_cross_gcc

+#!/bin/sh
+
+ set -e
+
+ case $1 in
+
+ -h) echo USAGE:
+ echo \ $0 [options] target arch_type kernel_version
+ echo \ \-h, --help: Display help
+ echo \ \-v, --version: Display version
+ echo \ \-c, --clean: Clean current directory
+ shift
+ exit 0;;
+ --help) echo USAGE:
+ echo \ $0 target arch_type kernel_version
+ echo \ \-h, --help: Display help
+ echo \ \-v, --version: Display version
+ echo \ \-c, --clean: Clean current directory
+ shift
+ exit 0;;
+ -v) echo build_cross_gcc version 1.2.0
+ shift
+ exit 0;;
+ --version) echo build_cross_gcc version 1.2.0
+ shift
+ exit 0;;
+ -c) rm -rf build-binutils build-gcc build-glibc
+ rm -rf \
+ ./gcc-8.2.0 \
+ ./cloog-0.18.4 \
+ ./gmp-6.1.2 \
+ ./glibc-2.28 \
+ ./binutils-2.31.1 \
+ ./mpfr-4.0.1 \
+ ./mpc-1.1.0 \
+ ./linux-3.18.1 \
+ ./isl-0.20
+ shift
+ exit 0;;
+ --clean) rm -rf build-binutils build-gcc build-glibc
+ rm -rf \ 
+ ./gcc-8.2.0 \
+ ./cloog-0.18.4 \
+ ./gmp-6.1.2 \
+ ./glibc-2.28 \
+ ./binutils-2.31.1 \
+ ./mpfr-4.0.1 \
+ ./mpc-1.1.0 \
+ ./linux-3.18.1 \
+ ./isl-0.20
+ shift
+ exit 0;;
+ esac
+
+ export major_version="$(echo $3 | cut -c1)"
+
+ wget https://ftpmirror.gnu.org/gnu/binutils/binutils-2.31.1.tar.xz
+ wget https://ftpmirror.gnu.org/gnu/gcc/gcc-8.2.0/gcc-8.2.0.tar.xz
+ wget https://mirrors.edge.kernel.org/pub/linux/kernel/v"$major_version".x/linux-$3.tar.xz
+ wget https://ftpmirror.gnu.org/gnu/libc/glibc-2.28.tar.xz
+ wget https://ftpmirror.gnu.org/gnu/mpfr/mpfr-4.0.1.tar.xz
+ wget https://ftpmirror.gnu.org/gnu/gmp/gmp-6.1.2.tar.xz
+ wget https://ftpmirror.gnu.org/gnu/mpc/mpc-1.1.0.tar.gz
+ wget http://isl.gforge.inria.fr/isl-0.20.tar.bz2
+ wget https://www.bastoul.net/cloog/pages/download/cloog-0.18.4.tar.gz
+
+ for tar in *.tar*; do tar xpf $tar; done
+
+ rm -f \
+ ./glibc-2.28.tar.xz \
+ ./gmp-6.1.2.tar.xz \
+ ./gcc-8.2.0.tar.xz \
+ ./binutils-2.31.1.tar.xz \
+ ./linux-3.18.1.tar.xz \
+ ./mpfr-4.0.1.tar.xz \
+ ./cloog-0.18.4.tar.gz \
+ ./isl-0.20.tar.bz2 \
+ ./mpc-1.1.0.tar.gz \
+
+ mkdir build-binutils || true
+ cd build-binutils
+ ../binutils-2.31.1/configure --prefix=/usr/local --target=$1
+ make -j$(nproc)
+ make install
+ cd ..
+ cd linux-$3
+ make ARCH=$2 INSTALL_HDR_PATH=/usr/local/$1 headers_install
+ cd ..
+ mkdir build-gcc || true
+ cd build-gcc
+ ../gcc-8.2.0/configure --prefix=/usr/local --target=$1 --enable-languages=c,c++,fortran --disable-multilib
+ make -j$(nproc) all-gcc
+ make install-gcc
+ cd ..
+ mkdir build-glibc || true
+ cd build-glibc
+ ../glibc-2.28/configure --disable-libmpx --prefix=/usr/local/$1 --disable-werror --enable-shared --build=$MACHTYPE --host=$1 --with-headers=/usr/local/$1/include --disable-multilib libc_cv_forced_unwind=yes
+ make install-bootstrap-headers=yes install-headers
+ make -j$(nproc) csu/subdir_lib
+ install csu/crt1.o csu/crti.o csu/crtn.o /usr/local/$1/lib
+ $1-gcc -nostdlib -nostartfiles -shared -x c /dev/null -o /usr/local/$1/lib/libc.so
+ touch /usr/local/$1/include/gnu/stubs.h
+ cd ..
+ cd build-gcc
+ make -j$(nproc) all-target-libgcc
+ make install-target-libgcc
+ cd ..
+ cd build-glibc
+ make -j$(nproc)
+ make install
+ cd ..
+ cd build-gcc
+ make -j$(nproc)
+ make install
+ cd ..
+ $1-gcc -v