Replace _stricmp with absl::EqualsIgnoreCase

All uses check only for equality.

Bug: webrtc:6424
Change-Id: I8755dde02370c89dbc2226bb703664c9e4f88bdb
Reviewed-on: https://webrtc-review.googlesource.com/c/106383
Commit-Queue: Niels Moller <nisse@webrtc.org>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#25274}
diff --git a/rtc_base/BUILD.gn b/rtc_base/BUILD.gn
index 2b13212..36e4f57 100644
--- a/rtc_base/BUILD.gn
+++ b/rtc_base/BUILD.gn
@@ -704,6 +704,7 @@
     "third_party/base64",
     "third_party/sigslot",
     "//third_party/abseil-cpp/absl/memory",
+    "//third_party/abseil-cpp/absl/strings",
     "//third_party/abseil-cpp/absl/types:optional",
   ]
   public_deps = [