Add video_encoder to default build

under the same conditions as video_replay.
Drive-by: fix typos

BUG=webrtc:15210

Change-Id: I6d288b2f7c8e2101192556eada6b28c82bfabf2f
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/308723
Reviewed-by: Markus Handell <handellm@webrtc.org>
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Commit-Queue: Philipp Hancke <phancke@microsoft.com>
Cr-Commit-Position: refs/heads/main@{#40355}
diff --git a/BUILD.gn b/BUILD.gn
index a13df86..47476e4 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -70,6 +70,7 @@
         "pc:slow_peer_connection_unittests",
         "pc:svc_tests",
         "rtc_tools:rtp_generator",
+        "rtc_tools:video_encoder",
         "rtc_tools:video_replay",
         "stats:rtc_stats_unittests",
         "system_wrappers:system_wrappers_unittests",
diff --git a/rtc_tools/video_encoder/video_encoder.cc b/rtc_tools/video_encoder/video_encoder.cc
index 9f0100e..4c8835c 100644
--- a/rtc_tools/video_encoder/video_encoder.cc
+++ b/rtc_tools/video_encoder/video_encoder.cc
@@ -28,18 +28,18 @@
 ABSL_FLAG(std::string,
           video_codec,
           "",
-          "Sepcify codec of video encoder: vp8, vp9, h264, av1");
+          "Specify codec of video encoder: vp8, vp9, h264, av1");
 ABSL_FLAG(std::string,
           scalability_mode,
           "L1T1",
-          "Sepcify scalability mode of video encoder");
+          "Specify scalability mode of video encoder");
 
 ABSL_FLAG(uint32_t,
           raw_frame_generator,
           0,
-          "Sepcify SquareFrameGenerator or SlideGenerator.\n"
+          "Specify SquareFrameGenerator or SlideGenerator.\n"
           "0: SquareFrameGenerator, 1: SlideGenerator");
-ABSL_FLAG(uint32_t, width, 1280, "Sepcify width of video encoder");
+ABSL_FLAG(uint32_t, width, 1280, "Specify width of video encoder");
 ABSL_FLAG(uint32_t, height, 720, "Specify height of video encoder");
 
 ABSL_FLAG(std::string,