Small fixes for unused argument warnings w/ Makefile.standalone "sb" target.

BUG=none
R=jpp@chromium.org, kschimpf@google.com

Review URL: https://codereview.chromium.org/1219883003.
diff --git a/src/IceBrowserCompileServer.cpp b/src/IceBrowserCompileServer.cpp
index d2654e3..5a5b970 100644
--- a/src/IceBrowserCompileServer.cpp
+++ b/src/IceBrowserCompileServer.cpp
@@ -101,6 +101,7 @@
 
 void fatalErrorHandler(void *UserData, const std::string &Reason,
                        bool GenCrashDialog) {
+  (void)GenCrashDialog;
   BrowserCompileServer *Server =
       reinterpret_cast<BrowserCompileServer *>(UserData);
   Server->setFatalError(Reason);