Prefix flag macros with WEBRTC_.

Macros defined in rtc_base/flags.h are intended to be used to define
flags in WebRTC's binaries (e.g. tests).

They are currently not prefixed and this could cause problems with
downstream clients since these names are quite common.

This CL adds the 'WEBRTC_' prefix to them.

Generated with:

for x in DECLARE DEFINE; do
  for y in bool int float string FLAG; do
    git grep -l "\b$x\_$y\b" | \
    xargs sed -i "s/\b$x\_$y\b/WEBRTC_$x\_$y/g"
  done
done
git cl format

Bug: webrtc:9884
Change-Id: I7b524762b6a3e5aa5b2fc2395edd3e1a0fe72591
Reviewed-on: https://webrtc-review.googlesource.com/c/106682
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#25270}
diff --git a/modules/audio_coding/neteq/tools/rtp_encode.cc b/modules/audio_coding/neteq/tools/rtp_encode.cc
index 5065ca1..f48b04d 100644
--- a/modules/audio_coding/neteq/tools/rtp_encode.cc
+++ b/modules/audio_coding/neteq/tools/rtp_encode.cc
@@ -40,20 +40,24 @@
 namespace {
 
 // Define command line flags.
-DEFINE_bool(list_codecs, false, "Enumerate all codecs");
-DEFINE_string(codec, "opus", "Codec to use");
-DEFINE_int(frame_len, 0, "Frame length in ms; 0 indicates codec default value");
-DEFINE_int(bitrate, 0, "Bitrate in kbps; 0 indicates codec default value");
-DEFINE_int(payload_type,
-           -1,
-           "RTP payload type; -1 indicates codec default value");
-DEFINE_int(cng_payload_type,
-           -1,
-           "RTP payload type for CNG; -1 indicates default value");
-DEFINE_int(ssrc, 0, "SSRC to write to the RTP header");
-DEFINE_bool(dtx, false, "Use DTX/CNG");
-DEFINE_int(sample_rate, 48000, "Sample rate of the input file");
-DEFINE_bool(help, false, "Print this message");
+WEBRTC_DEFINE_bool(list_codecs, false, "Enumerate all codecs");
+WEBRTC_DEFINE_string(codec, "opus", "Codec to use");
+WEBRTC_DEFINE_int(frame_len,
+                  0,
+                  "Frame length in ms; 0 indicates codec default value");
+WEBRTC_DEFINE_int(bitrate,
+                  0,
+                  "Bitrate in kbps; 0 indicates codec default value");
+WEBRTC_DEFINE_int(payload_type,
+                  -1,
+                  "RTP payload type; -1 indicates codec default value");
+WEBRTC_DEFINE_int(cng_payload_type,
+                  -1,
+                  "RTP payload type for CNG; -1 indicates default value");
+WEBRTC_DEFINE_int(ssrc, 0, "SSRC to write to the RTP header");
+WEBRTC_DEFINE_bool(dtx, false, "Use DTX/CNG");
+WEBRTC_DEFINE_int(sample_rate, 48000, "Sample rate of the input file");
+WEBRTC_DEFINE_bool(help, false, "Print this message");
 
 // Add new codecs here, and to the map below.
 enum class CodecType {