Single-thread RTOS configuration should not be forced

[neilt6]

I'm trying to switch my projects to the updated mbed classic and mbed-rtos libraries, but it appears that everything using the ARM micro toolchain is being built in a single-thread configuration. Whose bright idea was this? Why would I bother to include the RTOS library if I only wanted to use a single thread? And why should I have to choose between the ARM micro toolchain, and the RTOS library? I've been using the RTOS library on the smaller micros (e.g. LPC11U35) for years without issue, but these projects will no longer be feasible if I have to switch to the significantly more bloated ARM standard toolchain.