GCC cross-compiler building script

Supported architectures:

    Cross-compiler toolchain build script
    Possible target platforms are:
     aarch64    ARM64
     amd64      AMD64 (x86-64, x64)
     arm32      ARM
     armhf      ARM hard float
     ia32       IA-32 (x86, i386)
     ia64       IA-64 (Itanium)
     mips32     MIPS little-endian 32b
     mips32eb   MIPS big-endian 32b
     mips64     MIPS little-endian 64b
     ppc32      32-bit PowerPC
     ppc64      64-bit PowerPC
     sparc32    SPARC V8
     sparc64    SPARC V9
     lm32       LatticeMico32

    The toolchain is installed into directory specified by the
    CROSS_PREFIX environment variable. If the variable is not
    defined, /usr/local/cross/ is used as default.
    
    If '--install no' is present, the toolchain still uses the
    CROSS_PREFIX as the target directory but the installation
    copies the files into PKG/ subdirectory without affecting
    the actual root file system. That is only useful if you do
    not want to run the script under the super user.
    
    If '--enable-cxx' is present, C++ tools (e. g. g++) are built.

Dependencies to install on Debian-based distros

sudo apt install sed flex bison gzip gettext zlib texinfo libelf-dev libgomp1 make tar libgmp-dev libmpfr-dev libmpc-dev libisl-dev build-essential

Building

Example 1: Build a cross-compiler for 32-bit PowerPC using 4 cores without installing:

 ./toolchain.py --arch ppc32 --install no --cores 4

Example 2: Build a cross-compiler for 64-bit ARM with C++ support using 4 cores without installing:

 ./toolchain.py --arch aarch64 --install no --cores 4 --enable-cxx

Example 3: Build and install a cross-compiler for 32-bit ARM (default install directory is /usr/local/cross, specify another one by exporting CROSS_PREFIX environment variable), note that you need 'sudo' to install:

 sudo ./toolchain.py --arch arm32 --install yes