mbed-drivers - error missing cstddef

This is the line which fails to build for some users when using ubuntu, or even on macs.

Found reported in various places, various "fixes-" but all seemed to be effective, here are some references:
http://forums.mbed.com/t/yotta-on-raspberry-pi-2/842/2 (reported with yotta + mbed OS)
https://github.com/tmk/tmk_keyboard/issues/212 (mbed 2 sdk, but same error with the same header, provides some additional information)
https://developer.mbed.org/forum/mbed/topic/5205 (I saw this first time back in 2014 in this thread)

@jaustin Any pointers?

Reproduce the missing-cstddef build failure on Ubuntu or macOS using the mbed-drivers build entry point; the issue does not name a source file or test. Trace the failing include and compare the referenced reports, then consider the issue complete when the project builds successfully on the affected platforms.

Written by the indexing model from the issue text.