Add setup.sh to build cross compiler

.gitignore

@@ -0,0 +1,5 @@
+/i686-elf-gcc/
+*.xz
+/build-*/
+/gcc-*/
+/binutils-*/

setup.sh

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+#!/bin/sh
+
+# First install the following commands:
+# * gcc
+# * make
+# * bison
+# * flex
+# * texi2any (texinfo package)
+# * wget
+# And the following libraries:
+# * gmp (libgmp-dev)
+# * mpc (libmpc-dev)
+# * mpfr (libmpfr-dev)
+
+BINUTILS_VERSION="2.35"
+GCC_VERSION="10.2.0"
+export PREFIX="$PWD/i686-elf-gcc"
+export PATH="$PWD/i686-elf-gcc/bin:$PATH"
+TARGET="i686-elf"
+
+if [ -e "i686-elf-gcc" ]; then
+  echo "Exiting since installation directory already present"
+  exit 0
+fi
+
+# Download archives.
+if [ ! -f binutils-$BINUTILS_VERSION.tar.xz ]; then
+  wget "https://ftp.gnu.org/gnu/binutils/binutils-$BINUTILS_VERSION.tar.xz"
+fi
+if [ ! -f gcc-$GCC_VERSION.tar.xz ]; then
+  wget "https://ftp.gnu.org/gnu/gcc/gcc-$GCC_VERSION/gcc-$GCC_VERSION.tar.xz"
+fi
+
+# Extract archives.
+tar xJf binutils-$BINUTILS_VERSION.tar.xz
+tar xJf gcc-$GCC_VERSION.tar.xz
+
+# Build binutils.
+rm -rf "build-binutils"
+mkdir "build-binutils"
+cd "build-binutils"
+  ../binutils-$BINUTILS_VERSION/configure \
+    --target="$TARGET" --prefix="$PREFIX" --with-sysroot --disable-nls \
+    --disable-werror
+  make
+  make install
+cd ..
+
+# Build gcc.
+rm -rf "build-gcc"
+mkdir "build-gcc"
+cd "build-gcc"
+  ../gcc-$GCC_VERSION/configure \
+    --target="$TARGET" --prefix="$PREFIX" --disable-nls \
+    --enable-languages=c --without-headers
+  make all-gcc
+  make all-target-libgcc
+  make install-gcc
+  make install-target-libgcc
+cd ..