[gn] Migrate more custom cflags from gyp to gn

test/cctest/BUILD.gn

 # Copyright 2016 The V8 project authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # The sources are kept automatically in sync with cctest.gyp.
 
 import("../../gni/v8.gni")
 
 gypi_values = exec_script("//build/gypi_to_gn.py",
                           [ rebase_path("cctest.gyp") ],
                           "scope",
                           [ "cctest.gyp" ])
 
 v8_executable("cctest") {
   testonly = true
 
-  sources = [
-    "$target_gen_dir/resources.cc",
-  ] + gypi_values.cctest_sources
+  sources = [ "$target_gen_dir/resources.cc" ] + gypi_values.cctest_sources
 
   if (v8_current_cpu == "arm") {
     sources += gypi_values.cctest_sources_arm
   } else if (v8_current_cpu == "arm64") {
     sources += gypi_values.cctest_sources_arm64
   } else if (v8_current_cpu == "x86") {
     sources += gypi_values.cctest_sources_ia32
   } else if (v8_current_cpu == "mips") {
     sources += gypi_values.cctest_sources_mips
   } else if (v8_current_cpu == "mipsel") {
@@ skipping 10 matching lines @@
     sources += gypi_values.cctest_sources_ppc
   } else if (v8_current_cpu == "s390" || v8_current_cpu == "s390x") {
     sources += gypi_values.cctest_sources_s390
   }
 
   if (is_linux) {
     # TODO(machenbach): Translate 'or OS=="qnx"' from gyp.
     sources += [ "test-platform-linux.cc" ]
   } else if (is_win) {
     sources += [ "test-platform-win32.cc" ]
-    # TODO(machenbach): Translate from gyp.
-    # "msvs_settings": {
-    #   "VCCLCompilerTool": {
-    #     # MSVS wants this for gay-{precision,shortest}.cc.
-    #     "AdditionalOptions": ["/bigobj"],
-    #   },
-    # },
   }
 
   configs = [
     "../..:external_config",
     "../..:internal_config_base",
   ]
 
   # TODO(machenbach): Translate from gyp.
-  #['v8_current_cpu=="ppc" or v8_current_cpu=="ppc64" \
-  #  or v8_current_cpu=="arm" or v8_current_cpu=="arm64" \
-  #  or v8_current_cpu=="s390" or v8_current_cpu=="s390x"', {
-  #  # disable fmadd/fmsub so that expected results match generated code in
-  #  # RunFloat64MulAndFloat64Add1 and friends.
-  #  'cflags': ['-ffp-contract=off'],
-  #}],
-
-  # TODO(machenbach): Translate from gyp.
   #["OS=="aix"", {
   #  "ldflags": [ "-Wl,-bbigtoc" ],
   #}],
 
   deps = [
     ":resources",
     "../..:v8_libplatform",
     "//build/config/sanitizers:deps",
     "//build/win:default_exe_manifest",
   ]
 
   if (is_component_build) {
     # cctest can't be built against a shared library, so we
     # need to depend on the underlying static target in that case.
     deps += [ "../..:v8_maybe_snapshot" ]
   } else {
     deps += [ "../..:v8" ]
   }
 
+  cflags = []
+  ldflags = []
+
+  if (v8_current_cpu == "ppc" || v8_current_cpu == "ppc64" ||
+      v8_current_cpu == "arm" || v8_current_cpu == "arm64" ||
+      v8_current_cpu == "s390" || v8_current_cpu == "s390x") {
+    # Disable fmadd/fmsub so that expected results match generated code in
+    # RunFloat64MulAndFloat64Add1 and friends.
+    cflags += [ "-ffp-contract=off" ]
+  }
+
   if (is_win) {
     # This warning is benignly triggered by the U16 and U32 macros in
     # bytecode-utils.h.
     # C4309: 'static_cast': truncation of constant value
-    cflags = [ "/wd4309" ]
+    cflags += [ "/wd4309" ]
+
+    # MSVS wants this for gay-{precision,shortest}.cc.
+    cflags += [ "/bigobj" ]
 
     # Suppress warnings about importing locally defined symbols.
     if (is_component_build) {
-      ldflags = [
+      ldflags += [
         "/ignore:4049",
         "/ignore:4217",
       ]
     }
   }
 }
 
 action("resources") {
   visibility = [ ":*" ]  # Only targets in this file can depend on this.
 
@@ skipping 46 matching lines @@
     "//build/win:default_exe_manifest",
   ]
 
   if (is_component_build) {
     # Same as cctest, we need to depend on the underlying static target.
     deps += [ "../..:v8_maybe_snapshot" ]
   } else {
     deps += [ "../..:v8" ]
   }
 }