[Buildroot] external buildroot toolchain: LD_LIBRARY_PATH needed

Thomas De Schampheleire patrickdepinguin+buildroot at gmail.com
Tue Sep 6 14:17:54 UTC 2011

Thomas, Yann, Peter?
Any ideas?

On Thu, Aug 25, 2011 at 11:07 AM, Thomas De Schampheleire
<patrickdepinguin+buildroot at gmail.com> wrote:
> On Wed, Aug 24, 2011 at 4:31 PM, Grant Edwards
> <grant.b.edwards at gmail.com> wrote:
>> On 2011-08-24, Thomas De Schampheleire <patrickdepinguin+buildroot at gmail.com> wrote:
>>> If I build a buildroot toolchain on machine A, package the
>>> output/host/usr directory and use that as an external toolchain on
>>> machine B, I get errors that cc1 cannot find libmpfr.so.4. The
>>> location of that library is hardcoded in some compiler tools, and
>>> since we are on another machine, the original location does not
>>> exist.
>>> I can work around this by specifying
>>> LD_LIBRARY_PATH=<buildroot>/output/host/opt/ext-toolchain/lib in the
>>> environment, but this is an annoying and not so clean solution.
>>> How is this supposed to work?
>> Generally, when you run a gcc from somewhere othern than the location
>> for which it was originally compled you use the --sysroot option on
>> the compiler command line to tell it where it's now installed.
>> I don't know if the buildroot toolchain has that enabled or not.  I
>> had a lot of problems trying to use a buildroot-generated toolchain as
>> an external toolchain (this was a year or two back) and switched to
>> using crosstool-ng to build my toolchains.
> The buildroot external-toolchain support uses a 'wrapper' command,
> that makes sure that --sysroot, --mtune and the like gets passed to
> the compiler.
> The sysroot originally is at
> output/host/opt/ext-toolchain/powerpc-unknown-linux-uclibc/sysroot
> and gets copied to:
> /repo/tdescham/buildroot/output/host/usr/powerpc-unknown-linux-uclibc/sysroot
> However, the missing library does not seem part of sysroot. It is located at
> output/host/opt/ext-toolchain/lib
> where libgmp, libmpfr, libexpat etc. reside.
> Maybe this wrapper should be adapted as to include the proper LD_LIBRARY_PATH?
> How does crosstool-ng handle this fixed-path problem?
> Thomas

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