help needed for builing gcc tool-chain

[Prashant Batra (prbatra)]

-----Original Message-----
From: Jonathan Wakely [mailto:jwakely.gcc@gmail.com] 
Sent: Sunday, February 12, 2012 1:55 AM
To: Prashant Batra (prbatra)
Cc: gcc-help@gcc.gnu.org
Subject: Re: help needed for builing gcc tool-chain

On 11 February 2012 19:17, Prashant Batra (prbatra) wrote:
> Thanks, Jonathan,
>
> I am able to install gcc 4.1.2 with following configuration:
> ../gcc-4.1.2/configure
--prefix=/auto/nobackup-bgl-mitg-dev56/prbatra/fresh/build/
--enable-languages=c,c++,objc
>
> Now, the tool-chain is present in "prefix" directory.
>
> In second try, to make the tool-chain relocatable, I used
--with-sysroot=<prefix-dir> while configuring.

GCC is always relocatable, you can move the installation and it will
work in a different location.

> It fails saying /usr/include directory is not present in the
<prefix-dir>.
> Have I missed something again?

Did you read the docs for --with-sysroot? It tells the build process
to use the headers and libraries under the sysroot directory instead
of the ones in /usr - so if you have no headers and libraries in the
sysroot directory then it will fail to find them.
[Prashant] I configured it like -
../gcc-4.1.2/configure
--prefix=/auto/nobackup-bgl-mitg-dev56/prbatra/fresh2/build/
--with-sysroot=/auto/nobackup-bgl-mitg-dev56/prbatra/fresh2/build/sysroo
t --enable-languages=c,c++,objc

The contents of sysroot dir are-
ls ../build/sysroot/
include  lib  lib64  libexec

So I have copied the include and libs into the sysroot failure.

Still it fails saying - "The directory that should contain system
headers does not exist:"


One more doubt in general:

The documentation of --with-sysroot says "sysroot will be searched for
target system headers, libraries and run time objects", but I am
building gcc at this stage, so if I am building gcc forsome target, how
are these target system headers be present there"