[OE-core] Does support for external toolchains working in current OE?

[Marcin Juszkiewicz]

For last few months I am working on fixing Linaro binary cross
toolchains and their support in OpenEmbedded. Got to point when they 
work (both AArch64 and ARMv7a ones) for single packages but problem 
starts when I want to create image...

11:14 hrw at puchatek:build$ bitbake core-image-minimal -g
Parsing of 1302 .bb files complete (1294 cached, 8 parsed). 1670 targets, 45 skipped, 0 masked, 0 errors.
NOTE: Resolving any missing task queue dependencies
NOTE: multiple providers are available for virtual/gettext (proxy-libintl, gettext)
NOTE: consider defining a PREFERRED_PROVIDER entry to match virtual/gettext
NOTE: Preparing runqueue
ERROR: Multiple .bb files are due to be built which each provide virtual/libc (/home/hrw/HDD/devel/canonical/aarch64/openembedded/repos/openembedded-core/meta/recipes-core/eglibc/eglibc_2.17.bb /home/hrw/HDD/devel/canonical/aarch64/openembedded/repos/meta-linaro/meta-linaro-toolchain/recipes-devtools/external-linaro-toolchain/external-linaro-toolchain.bb).
 This usually means one provides something the other doesn't and should.
ERROR: Multiple .bb files are due to be built which each provide virtual/arm-linux-gnueabihf-libc-for-gcc (/home/hrw/HDD/devel/canonical/aarch64/openembedded/repos/openembedded-core/meta/recipes-core/eglibc/eglibc_2.17.bb /home/hrw/HDD/devel/canonical/aarch64/openembedded/repos/meta-linaro/meta-linaro-toolchain/recipes-devtools/external-linaro-toolchain/external-linaro-toolchain.bb).
 This usually means one provides something the other doesn't and should.
ERROR: Multiple .bb files are due to be built which each provide virtual/libiconv (/home/hrw/HDD/devel/canonical/aarch64/openembedded/repos/openembedded-core/meta/recipes-core/eglibc/eglibc_2.17.bb /home/hrw/HDD/devel/canonical/aarch64/openembedded/repos/meta-linaro/meta-linaro-toolchain/recipes-devtools/external-linaro-toolchain/external-linaro-toolchain.bb).
 This usually means one provides something the other doesn't and should.
NOTE: PN build list saved to 'pn-buildlist'
NOTE: PN dependencies saved to 'pn-depends.dot'
NOTE: Package dependencies saved to 'package-depends.dot'
NOTE: Task dependencies saved to 'task-depends.dot'

Summary: There were 3 ERROR messages shown, returning a non-zero exit code.

All three virtual/ are provided by external-linaro-toolchain recipe... 

Is there any external toolchain which allows to create image with current
OpenEmbedded layers? 

TCMODE="external-sourcery" gives exactly same problem.