Add some RTC_EXPORT needed by Chromium.

These are needed by crrev.com/c/4165083.

Bug: chromium:1369096, webrtc:14131
Change-Id: Id0a46254b46cf866f2f3b7b07b97dc55066c047f
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/291117
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#39165}
diff --git a/rtc_base/BUILD.gn b/rtc_base/BUILD.gn
index 4a9a546..7d236bc 100644
--- a/rtc_base/BUILD.gn
+++ b/rtc_base/BUILD.gn
@@ -839,7 +839,7 @@
     "net_helpers.cc",
     "net_helpers.h",
   ]
-  deps = []
+  deps = [ "system:rtc_export" ]
   if (is_android) {
     deps += [ ":ifaddrs_android" ]
   }
@@ -1389,6 +1389,7 @@
     "net_helper.h",
   ]
   absl_deps = [ "//third_party/abseil-cpp/absl/strings" ]
+  deps = [ "system:rtc_export" ]
 }
 
 rtc_library("socket_adapters") {
diff --git a/rtc_base/net_helper.h b/rtc_base/net_helper.h
index 758c0fa..2dce911 100644
--- a/rtc_base/net_helper.h
+++ b/rtc_base/net_helper.h
@@ -13,13 +13,14 @@
 #include <string>
 
 #include "absl/strings/string_view.h"
+#include "rtc_base/system/rtc_export.h"
 
 // This header contains helper functions and constants used by different types
 // of transports.
 namespace cricket {
 
-extern const char UDP_PROTOCOL_NAME[];
-extern const char TCP_PROTOCOL_NAME[];
+RTC_EXPORT extern const char UDP_PROTOCOL_NAME[];
+RTC_EXPORT extern const char TCP_PROTOCOL_NAME[];
 extern const char SSLTCP_PROTOCOL_NAME[];
 extern const char TLS_PROTOCOL_NAME[];
 
diff --git a/rtc_base/net_helpers.h b/rtc_base/net_helpers.h
index 631c634..478cec3 100644
--- a/rtc_base/net_helpers.h
+++ b/rtc_base/net_helpers.h
@@ -20,6 +20,7 @@
 #endif
 
 #include "absl/strings/string_view.h"
+#include "rtc_base/system/rtc_export.h"
 
 namespace rtc {
 
@@ -28,8 +29,8 @@
 const char* inet_ntop(int af, const void* src, char* dst, socklen_t size);
 int inet_pton(int af, absl::string_view src, void* dst);
 
-bool HasIPv4Enabled();
-bool HasIPv6Enabled();
+RTC_EXPORT bool HasIPv4Enabled();
+RTC_EXPORT bool HasIPv6Enabled();
 
 }  // namespace rtc