Adding readme.md to compile tools

tools/README.md

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+# Building the tools needed to build the kernel
+
+## Install dependencies
+
+### Ubuntu/Debian
+```sh
+sudo apt install build-essential bison flex libgmp3-dev libmpc-dev libmpfr-dev texinfo libisl-dev gcc-multilib
+```
+
+### Fedora
+```sh
+sudo dnf install gcc gcc-c++ make bison flex gmp-devel libmpc-devel mpfr-devel texinfo isl-devel
+```
+
+### Others
+For others please check [OSDev Wiki Installing Dependencies](https://wiki.osdev.org/GCC_Cross-Compiler#Installing_Dependencies) section
+
+
+## Compile
+> This is compilling `GCC` version `14.x` and `binutils` version `2.43.x`, make sure your OS gcc and binutils are the same major version!
+
+
+### Setting up the environment
+First, create the prefix folder, from your project folder execute
+```sh
+mkdir $(pwd)/toolchain/
+export PREFIX="$(pwd)/toolchain/"
+export PATH="$PREFIX/bin:$PATH"
+```
+
+Set the target to be a i686
+```sh
+export TARGET=i686-elf
+```
+### Building `binutils`
+From your project folder execute:
+```sh
+mkdir -p tools/build/build-binutils
+cd tools/build/build-binutils
+../../binutils/configure --target=$TARGET --prefix="$PREFIX" --with-sysroot --disable-nls --disable-werror
+make -j$(($(nproc)-2))
+make install
+```
+
+To check what each flag does consult [OSDev Wiki](https://wiki.osdev.org/GCC_Cross-Compiler#Binutils)
+
+### Build `GCC`
+First, check if `binutils` is reachable from within `$PATH`
+```sh
+which i686-elf-ld | grep $PREFIX -q && echo "Found i686-elf-ld" || echo "NOT found i686-elf-ld"
+```
+
+If you see `Found i686-elf-ld` you are good to got, if not you have made some mistake on the steps above.
+
+Now, compile `GCC` and `libgcc`. From your project folder execute:
+```sh
+mkdir -p tools/build/build-gcc
+cd build-gcc
+../../gcc/configure --target=$TARGET --prefix="$PREFIX" --disable-nls --enable-languages=c,c++ --without-headers
+make all-gcc -j$(($(nproc)-2))
+make all-target-libgcc -j$(($(nproc)-2))
+make install-gcc
+make install-target-libgcc
+```
+
+
+## Finals
+Once everything is compile you should have some binaries inside `$PREFIX/bin`, mainly `i686-elf-gcc`, `i686-elf-ld`, `i686-elf-gdb`, `i686-elf-as` and `i686-elf-g++`.
+
+```sh
+ls $PREFIX/bin
+```