Re: Gcc build fails with test_real_width is negative

[Stefan Ring <stefanrin@gmail.com>]

On Thu, Dec 2, 2021 at 10:20 AM Stefan Ring <stefanrin@gmail.com> wrote:
>
> On Mon, Nov 29, 2021 at 8:40 PM Mr Dini via Gcc-help
> <gcc-help@gcc.gnu.org> wrote:
> >
> > I am sure this is not a common practice, but since I couldn't get gcc to compile and I am out of ideas as to why libgcc is not picking up the environment variables, I decided to share the chroot I am trying to build from.
> >
> > The file can be found here: https://mega.nz/file/qqBB2QKZ#mQVV3Vqyre6MYtdGJlx2rNq7el8Aiimr6uv4aTZR97g
> >
> > When I chroot I firstly run the command to populate the environment variables:
> >
> > . /opt/webos-sdk-x86_64/1.0.g/environment-setup-armv7a-neon-webos-linux-gnueabi
> >
> > Then execute the following commands to start the build process:
> >
> > cd /root/gcc-build
> >
> > CC="arm-webos-linux-gnueabi-gcc -march=armv7-a -mfpu=neon -mfloat-abi=softfp --sysroot=/opt/webos-sdk-x86_64/1.0.g/sysroots/armv7a-neon-webos-linux-gnueabi" CXX="arm-webos-linux-gnueabi-g++ -march=armv7-a -mfpu=neon -mfloat-abi=softfp --sysroot=/opt/webos-sdk-x86_64/1.0.g/sysroots/armv7a-neon-webos-linux-gnueabi" ../gcc-6.2.0/configure --prefix=/opt/webos-sdk-x86_64/1.0.g/sysroots/armv7a-neon-webos-linux-gnueabi --with-mpfr=/opt/webos-sdk-x86_64/1.0.g/sysroots/armv7a-neon-webos-linux-gnueabi --host=armv7a-linux-gnueabi --target=armv7a-linux-gnueabi --build=x86_64-linux-gnu
> >
> > make -j8
> >
> > Right now, the folder contains a state where it fails with stdio.h no such file or directory. If you skip the configure part and run make -j8 directly after setting the env vars, you can see what's going on.
> >
> > I appreciate any feedback!
> >
> > Thanks

Running the toolchain gcc with -v reveals that it was configured with
--with-sysroot=/not/exist. ;)

So I got a little creative and used:

mkdir /not
ln -s /opt/webos-sdk-x86_64/1.0.g/sysroots/armv7a-neon-webos-linux-gnueabi
/not/exist

Then I set:

export PATH=/opt/webos-sdk-x86_64/1.0.g/sysroots/x86_64-webossdk-linux/usr/bin/arm-webos-linux-gnueabi:$PATH

and only this. Forget about all the crap in
/opt/webos-sdk-x86_64/1.0.g/environment-setup-armv7a-neon-webos-linux-gnueabi!

Then

/root/gcc-6.2.0/configure
--prefix=/opt/webos-sdk-x86_64/1.0.g/sysroots/armv7a-neon-webos-linux-gnueabi
--build= --host=arm-webos-linux-gnueabi
--target=arm-webos-linux-gnueabi --with-sysroot=/
--with-build-sysroot=/opt/webos-sdk-x86_64/1.0.g/sysroots/armv7a-neon-webos-linux-gnueabi
--with-float=softfp --with-fpu=neon --with-arch=armv7-a
--enable-languages=c,c++ --disable-multilib
--with-mpfr=/opt/webos-sdk-x86_64/1.0.g/sysroots/armv7a-neon-webos-linux-gnueabi
make -j8

gives me a working build. At least a build running to completion. If
it actually works I cannot tell because I do not own the target. The
--with-build-sysroot is not strictly necessary because of the
/not/exist trick, but I consider it good taste. I’m also not sure
about the --with-sysroot=/. It may or may not help or hurt. Also, your
--prefix is probably not the best idea. Just use something short like
/usr/gcc6 or similar, and install with make install
DESTDIR=<somewhere>.