linux: fix missing includes and warnings

Change-Id: If83d74d86f4792ad8f8c4c62116457d1126ae9e9
Reviewed-on: https://chromium-review.googlesource.com/c/crashpad/crashpad/+/3404959
Reviewed-by: Mark Mentovai <mark@chromium.org>
Commit-Queue: Joshua Peraza <jperaza@chromium.org>
diff --git a/client/crashpad_client_linux.cc b/client/crashpad_client_linux.cc
index 5e53459..35742be 100644
--- a/client/crashpad_client_linux.cc
+++ b/client/crashpad_client_linux.cc
@@ -28,6 +28,8 @@
 #include <sys/wait.h>
 #include <unistd.h>
 
+#include <atomic>
+
 #include "base/logging.h"
 #include "base/strings/stringprintf.h"
 #include "build/build_config.h"
diff --git a/client/crashpad_client_linux_test.cc b/client/crashpad_client_linux_test.cc
index e58352b..4a2bb41 100644
--- a/client/crashpad_client_linux_test.cc
+++ b/client/crashpad_client_linux_test.cc
@@ -223,7 +223,10 @@
 
 bool HandleCrashSuccessfully(int, siginfo_t*, ucontext_t*) {
   siglongjmp(do_crash_sigjmp_env, 1);
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wunreachable-code-return"
   return true;
+#pragma clang diagnostic pop
 }
 
 void DoCrash(const StartHandlerForSelfTestOptions& options,