Re: Building a host-isolated gcc without faking cross-compiling

[Lance Fredrickson <lancethepants@gmail.com>]

I think you probably want |--with-native-system-header-dir

|
|--with-native-system-header-dir=dirname|

    Specifies thatdirnameis the directory that contains native system
    header files, rather than/usr/include. This option is most useful if
    you are creating a compiler that should be isolated from the system
    as much as possible. It is most commonly used with
    the--with-sysrootoption and will cause GCC to searchdirnameinside
    the system root specified by that option.

Lance

On 9/10/2021 10:54 AM, Anthony de Almeida Lopes via Gcc-help wrote:
> I'd like to build gcc for a chroot on my current system. Linux From
> Scratch uses a method of faking a cross compiler by modifying the vendor
> field of the target string. For example, changing x86_64-pc-linux-gnu to
> x86_64-lfs-linux-gnu. I'd like to know if there's a way of avoiding
> this. While GCC builds fine for my host natively and it builds fine with
> the LFS method, I have so far been unable to build a host isolated copy
> any other way.
>
> I understand the recommended order is to build binutils and gcc first,
> then build glibc with them and finally rebuild gcc against that glibc.
>
> # I built binutils like this
>
> ../configure   \
>      --prefix=$DISTRO/root/bootstrap \
>      --with-sysroot=$DISTRO  \
>      --disable-nls \
>      --disable-werror
>
> && make -j6 && make -j1 install
>
> # Then I tried to build gcc like this
>
> ../configure                                       \
>       --prefix=$DISTRO/tools                         \
>       --with-glibc-version=2.11                      \
>       --with-sysroot=$DISTRO                         \
>       --with-newlib                                  \
>       --without-headers                              \
>       --enable-initfini-array                        \
>       --disable-nls                                  \
>       --disable-shared                               \
>       --disable-multilib                             \
>       --disable-decimal-float                        \
>       --disable-threads                              \
>       --disable-libatomic                            \
>       --disable-libgomp                              \
>       --disable-libquadmath                          \
>       --disable-libssp                               \
>       --disable-libvtv                               \
>       --disable-libstdcxx                            \
>       --enable-languages=c,c++
>
> && make -j6 && make -j1 install
>
> But this fails with a bunch of undefined references to the ZSTD
> namespace such as ZSTD_getErrorName from gcc/lto-compress.c. I assume
> this means that ./configure has detected that my host system has libzstd
> but it's trying to look for them in the sysroot, where it obviously
> can't find them. This happens even if I use --disable-lto.
>
> Build System (Arch Linux): linux 5.13.13, glibc 2.33, binutils 2.36.1,
> gcc 11.1.0
> Target System: linux 5.13.12, glibc 2.34, binutils 2.37, gcc 11.2.0
>
> So I'd like to know if I should continue like this, and if so how, or if
> there is a better (maybe canonical) way of building a host-isolated
> compiler?
>
> - Anthony
>
>