fix(demangle): Unbreak GitHub Action Windows builds (#891)

The 12.13.0 release and pull request #885 specifically broke GitHub
Action based Windows builds. The reason seems to be that the Swift
library upgrade now relies on C++17 features and the GitHub Actions
Windows image uses MSVC 2022, which requires an explicit opt-in to
those. The provided -std=c++17 works on GCC and similar, but does not
have any effect on MSVC.
To fix the build, add the flag that MSVC understands for opting in to
the new standard.

Author: d-e-s-o

CHANGELOG.md

@@ -2,16 +2,21 @@
 
 ## Unreleased
 
-- Fix new clippy lints ([#889](https://github.com/getsentry/symbolic/pull/889))
-- Run `cargo update` ([#888](https://github.com/getsentry/symbolic/pull/888))
+**Fixes**
+
+- Fixed GHA-based Windows builds ([#891](https://github.com/getsentry/symbolic/pull/891)).
 
 ## 12.13.1
 
+**Fixes**
+
 - Fixed a compilation issue with older GCC compilers. ([#886](https://github.com/getsentry/symbolic/pull/886))
 
 ## 12.13.0
 
-- Update libswift demangle to v6.0.3. ([#885](https://github.com/getsentry/symbolic/pull/885))
+**Features**
+
+- Updated libswift demangle to v6.0.3. ([#885](https://github.com/getsentry/symbolic/pull/885))
 
 ## 12.12.4
 
@@ -34,7 +39,7 @@
 
 ## 12.12.1
 
-**Features**:
+**Features**
 
 - feat(js): Sourcemap debug IDs can now be read from the `"debugId"` field in addition to
   `"debug_id"` ([#870](https://github.com/getsentry/symbolic/pull/870)).

symbolic-demangle/build.rs

@@ -18,6 +18,7 @@ fn main() {
                 "vendor/swift/lib/Demangling/Remangler.cpp",
             ])
             .flag_if_supported("-std=c++17")
+            .flag_if_supported("/std:c++17")
             .flag_if_supported("-fpermissive")
             .flag_if_supported("-Wno-changes-meaning")
             .flag("-DLLVM_DISABLE_ABI_BREAKING_CHECKS_ENFORCING=1")