Make compiles fail when __DATE__, __TIME__, or __TIMESTAMP_ are used.

build/config/compiler/BUILD.gn

 # Copyright (c) 2013 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//build/config/android/config.gni")
 import("//build/config/chrome_build.gni")
 import("//build/config/compiler/compiler.gni")
 import("//build/config/nacl/config.gni")
 import("//build/toolchain/cc_wrapper.gni")
 import("//build/toolchain/toolchain.gni")
@@ skipping 949 matching lines @@
 
       # Don't warn about "maybe" uninitialized. Clang doesn't include this
       # in -Wall but gcc does, and it gives false positives.
       cflags += [ "-Wno-maybe-uninitialized" ]
     }
   }
 
   # Common Clang and GCC warning setup.
   if (!is_win || is_clang) {
     cflags += [
+      # Disable __DATE__ and __TIME__ to help make builds deterministic.

[Nico, 2016/08/25 19:20:03]

Maybe add a note along the lines of "If this fires in third-party code you're
adding, make that third-party code not use __DATE__ / __TIME__. Do not disable
this warning, we must have deterministic builds"

+      "-Wdate-time",
+
       # Disables.
       "-Wno-missing-field-initializers",  # "struct foo f = {0};"
       "-Wno-unused-parameter",  # Unused function parameters.
     ]
   }
 
   if (is_chromeos) {
     # TODO(thakis): Remove, http://crbug.com/263960
     if (is_clang) {
       cflags_cc += [ "-Wno-reserved-user-defined-literal" ]
@@ skipping 601 matching lines @@
 
 if (is_ios || is_mac) {
   # On Mac and iOS, this enables support for ARC (automatic ref-counting).
   # See http://clang.llvm.org/docs/AutomaticReferenceCounting.html.
   config("enable_arc") {
     common_flags = [ "-fobjc-arc" ]
     cflags_objc = common_flags
     cflags_objcc = common_flags
   }
 }