Windows: Build the pe_image target as C++17 (see issue #2819)

This works around a bug in the Visual C++ standard library where the
std::is_integral templates are exported instead of inlined when building
with C++14. See also https://bugs.llvm.org/show_bug.cgi?id=42027.

patch/patch.cfg

@@ -488,10 +488,10 @@ patches = [
     'name': 'win_tool_wrapper_1033106',
   },
   {
-    # Windows: Build the double_conversion target as C++17 to avoid export of
-    # std::is_integral templates that should be inlined.
+    # Windows: Build targets as C++17 to avoid export of std::is_integral
+    # templates in cef_sandbox that should be inlined.
     # https://bitbucket.org/chromiumembedded/cef/issues/2819
-    'name': 'win_double_conversion_2819',
+    'name': 'win_cpp17_msvc_sandbox_2819',
   },
   {
     # libxml access is now limited to targets audited by the Security Team.

patch/patches/win_cpp17_msvc_sandbox_2819.patch

@@ -14,3 +14,15 @@ index 0083efdcd9c8..6f647c31e28a 100644
  }
  
  static_library("double_conversion") {
+diff --git base/win/BUILD.gn base/win/BUILD.gn
+index 33a38267a658..0d54f224d31c 100644
+--- base/win/BUILD.gn
++++ base/win/BUILD.gn
+@@ -31,4 +31,7 @@ static_library("pe_image") {
+     "pe_image.cc",
+     "pe_image.h",
+   ]
++
++  # Build as C++17 to avoid export of templates that should be inlined.
++  cflags_cc = [ "/std:c++17" ]
+ }