external-toolchain-csl: allow linux-libc-headers
external-toolchain-csl: allow linux-libc-headers

If PREFERRED_PROVIDER_linux-libc-headers is defined as anything
other than external-toolchain-csl then don't PROVIDE, install or
stage the linux headers packaged with the CSL toolchain.

(Updated by Tom Rini to not modify local.conf.sample yet and to use
cp + rm -rf rather than rsync)

Signed-off-by: Ben Gardiner <70df8feb3ef5e98f393abcbbb2227739b5f9dc64@nanometrics.ca>
Tested-by: Andrea Galbusera <gizero@gmail.com>
Signed-off-by: Tom Rini <4c3d5c8f8c21c27dd329bd585f481113514551fd@mentor.com>
(cherry picked from commit 3116ad58e507c6e5dc7b7249f521c395db586b9f)

Signed-off-by: Ben Gardiner <70df8feb3ef5e98f393abcbbb2227739b5f9dc64@nanometrics.ca>
Acked-by: Denys Dmytriyenko <d29de71aea38aad3a87d486929cb0aad173ae612@ti.com>
Signed-off-by: Tom Rini <4c3d5c8f8c21c27dd329bd585f481113514551fd@mentor.com>

rascalmicro/openembedded-rascal,rascalmicro/openembedded-rascal,rascalmicro/openembedded-rascal,rascalmicro/openembedded-rascal,rascalmicro/openembedded-rascal,rascalmicro/openembedded-rascal,rascalmicro/openembedded-rascal,rascalmicro/openembedded-rascal