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/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" ]
+ }