win: Don't build /FORCE:DuplicateRes targets with /WX.

/FORCE:MultipleRes makes duplicate resources emit a warning instead of
an error, but /WX converts all warnings into errors.

TBR=hans

Bug: 958955
Change-Id: I0764edbcd9f13f7412e160075985ce611675dc4c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1594701
Commit-Queue: Nico Weber <thakis@chromium.org>
Reviewed-by: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#656390}

build/config/BUILDCONFIG.gn

@@ -432,6 +432,7 @@ default_compiler_configs = [
   "//build/config/compiler:default_stack_frames",
   "//build/config/compiler:default_symbols",
   "//build/config/compiler:export_dynamic",
+  "//build/config/compiler:fatal_linker_warnings_win",
   "//build/config/compiler:no_exceptions",
   "//build/config/compiler:no_rtti",
   "//build/config/compiler:runtime_library",

build/config/compiler/BUILD.gn

@@ -1085,7 +1085,8 @@ config("compiler_deterministic") {
   }
 
   # Makes builds independent of absolute file path.
-  if (symbol_level != 0 && is_clang && strip_absolute_paths_from_debug_symbols) {
+  if (symbol_level != 0 && is_clang &&
+      strip_absolute_paths_from_debug_symbols) {
     # If debug option is given, clang includes $cwd in debug info by default.
     # For such build, this flag generates reproducible obj files even we use
     # different build directory like "out/feature_a" and "out/feature_b" if
@@ -1173,7 +1174,8 @@ config("compiler_arm") {
 config("assembler_debug_dir") {
   # TODO(thakis): Once openmax_dl no longer uses -fno-integrated-as, move
   # this behind the -fdebug-compilation-dir cflags in the "compiler" config.
-  if (symbol_level != 0 && is_clang && strip_absolute_paths_from_debug_symbols) {
+  if (symbol_level != 0 && is_clang &&
+      strip_absolute_paths_from_debug_symbols) {
     if (!is_win) {
       # We don't use clang -cc1as on Windows (yet? https://crbug.com/762167)
       asmflags = [ "-Wa,-fdebug-compilation-dir,." ]
@@ -1242,9 +1244,6 @@ config("default_warnings") {
     if (treat_warnings_as_errors) {
       cflags += [ "/WX" ]
     }
-    if (fatal_linker_warnings) {
-      ldflags += [ "/WX" ]
-    }
 
     cflags += [
       # Warnings permanently disabled:
@@ -1509,6 +1508,14 @@ config("default_warnings") {
   }
 }
 
+config("fatal_linker_warnings_win") {
+  # TODO(thakis): Move this back into default_warnings once
+  # https://crbug.com/958955 is resolved.
+  if (is_win && fatal_linker_warnings) {
+    ldflags = [ "/WX" ]
+  }
+}
+
 # chromium_code ---------------------------------------------------------------
 #
 # Toggles between higher and lower warnings for code that is (or isn't)

chrome/credential_provider/test/BUILD.gn

@@ -55,5 +55,6 @@ test("gcp_unittests") {
   if (is_win && llvm_force_head_revision) {
     # TODO(https://crbug.com/958955): Fix dupes and remove this flag.
     ldflags = [ "/FORCE:MultipleRes" ]
+    configs -= [ "//build/config/compiler:fatal_linker_warnings_win" ]
   }
 }

chrome/test/BUILD.gn

@@ -4552,6 +4552,7 @@ test("unit_tests") {
     if (llvm_force_head_revision) {
       # TODO(https://crbug.com/958955): Fix dupes and remove this flag.
       ldflags += [ "/FORCE:MultipleRes" ]
+      configs -= [ "//build/config/compiler:fatal_linker_warnings_win" ]
     }
 
     if (is_chrome_branded) {
@@ -5779,6 +5780,7 @@ if (!is_android && !is_fuchsia) {
       if (llvm_force_head_revision) {
         # TODO(https://crbug.com/958955): Fix dupes and remove this flag.
         ldflags = [ "/FORCE:MultipleRes" ]
+        configs -= [ "//build/config/compiler:fatal_linker_warnings_win" ]
       }
     } else {
       sources -= [ "../app/chrome_version.rc.version" ]