how to skip building the druntime and phobos when building ldc?

[dangbinghoo]

On Friday, 8 November 2019 at 13:31:00 UTC, kinke wrote:
> On Friday, 8 November 2019 at 10:44:41 UTC, dangbinghoo wrote:
>> howto skip building the runtime and phobos?
>
> Don't build the `all` target, but `ldc2` (and optionally 
> `ldmd2`) only: ninja/make ldc2

thank you!

and i have another question:

what should to do to make the druntime building for xtensa esp32? 
druntime must depends on an OS? how the d compiler determing the 
version POSIX? esp32 is mcu platform, rightnow i can only use the 
ldc bare-metal style.