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

build/config/compiler/BUILD.gn

Index: build/config/compiler/BUILD.gn
diff --git a/build/config/compiler/BUILD.gn b/build/config/compiler/BUILD.gn
index 5e6d53095474bd9dcaaedf8b2d818170ffb79ed7..beacb49a5cb861fd3cacdde3880eab2f945cca2d 100644
--- a/build/config/compiler/BUILD.gn
+++ b/build/config/compiler/BUILD.gn
@@ -967,6 +967,9 @@ config("default_warnings") {
   # 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.