Make transient suppression optionally excludable via defines This allows clients to exclude the transient suppression submodule from WebRTC builds, by defining WEBRTC_EXCLUDE_TRANSIENT_SUPPRESSOR. The changes have been shown to be bitexact for a test dataset (when the flag is _not_ defined.) No-Try: True Bug: webrtc:11226, webrtc:11292 Change-Id: I6931c82a280a9b40a53ee1c2a9820ed9e674a9a5 Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/171421 Commit-Queue: Sam Zackrisson <saza@webrtc.org> Reviewed-by: Karl Wiberg <kwiberg@webrtc.org> Reviewed-by: Per Åhgren <peah@webrtc.org> Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org> Cr-Commit-Position: refs/heads/master@{#30978}

diff --git a/native-api.md b/native-api.md
index 18d074e..2c19327 100644
--- a/native-api.md
+++ b/native-api.md

@@ -106,3 +106,11 @@
 macro for you.
 
 [metrics_h]: https://webrtc.googlesource.com/src/+/master/system_wrappers/include/metrics.h
+
+## `WEBRTC_EXCLUDE_TRANSIENT_SUPPRESSOR`
+The transient suppressor functionality in the audio processing module is not
+always used. If you wish to exclude it from the build in order to preserve
+binary size, then define the preprocessor macro
+`WEBRTC_EXCLUDE_TRANSIENT_SUPPRESSOR`. If you use GN, you can just set the GN
+argument `rtc_exclude_transient_suppressor` to true and GN will define the macro
+for you.