Currently, only for the images themselves static libraries can be added by specifying staticdev-pkgs as option for EXTRA_IMAGE_FEATURES or IMAGE_FEATURES. For the toolchain (meta-toolchain-sdk), this option must be added to SDKIMAGE_FEATURES too. Tested with: "master:78983e939ab17f02f8911c8b0d0e326b419856b9". See bug 2531 for other comments.
This doesn't seem to be a bug, the user needs to configure the system to provide what they need, setting IMAGE_FEATURES and/or SDKIMAGE_FEATURES as appropriate?
The missing piece (not mentioned) is SDKIMAGE_FEATURES is not supported for non-image SDKs.
Could we drop meta-toolchain/meta-toolchain-sdk in this cycle?
We're deprecating meta-toolchain-sdk for 1.6 in favour of -c populate_sdk, which supports SDKIMAGE_FEATURES for those who want -staticdev packages in the SDK. Given that, I'm marking this as WONTFIX.