Introduce some placeholder build targets
Introduce some placeholder build targets

So that users can add dependencies on them, and not break when a bunch
of headers move out of rtc_base:rtc_base.

Bug: webrtc:9987
Change-Id: Iecd5dd903cb8b97cb6f051e3a0cb6df7f8ba22b3
Reviewed-on: https://webrtc-review.googlesource.com/c/113425
Reviewed-by: Mirko Bonadei <d2c43c210eae6feef04f53bae50885e8152edcca@webrtc.org>
Commit-Queue: Karl Wiberg <2c708eb0a58047bf403399f50b3da33ffd2dd444@webrtc.org>
Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#25923}
TimothyGu/libilbc,TimothyGu/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc