msrv: fix Jiff build on Windows for Rust 1.71

I think older Rust versions were more paranoid about leaking types with
a more restricted scope. So just switch to `pub`.

We test this in CI, but only the build. Since dev dependencies have much
higher MSRVs.

Fixes #566

Author: BurntSushi

.github/workflows/ci.yml

@@ -355,6 +355,19 @@ jobs:
     # - name: Run integration tests
       # run: cargo test --test integration
 
+  # Same as above, but for Windows. The MSRV is technically higher because Jiff
+  # inherits the MSRV of system-level dependencies (like `windows-link`).
+  msrv-win:
+    runs-on: windows-latest
+    steps:
+    - name: Checkout repository
+      uses: actions/checkout@v5
+    - name: Install Rust
+      uses: dtolnay/rust-toolchain@master
+      with:
+        toolchain: 1.71.1
+    - run: cargo build --verbose
+
   # This job tests that examples outside the workspace build.
   #
   # These are outside the workspace because their dependency graphs are

src/tz/system/windows/ffi.rs

@@ -1,16 +1,21 @@
-pub(super) const TIME_ZONE_ID_INVALID: u32 = 0xffffffff;
+pub const TIME_ZONE_ID_INVALID: u32 = 0xffffffff;
 
+// MSRV(??): Must be marked as public to avoid errors in older Rust compilers.
+// Rust 1.71 needs this. But Rust 1.95 does not. I'm not sure where the cross
+// over point is, but it'd be nice to tighten this up a bit. In any case, this
+// isn't actually re-exported anywhere in Jiff's public API, so it's fine.
+// ---AG
 #[repr(C)]
-pub(super) struct DYNAMIC_TIME_ZONE_INFORMATION {
+pub struct DYNAMIC_TIME_ZONE_INFORMATION {
     bias: i32,
     standard_name: [u16; 32],
     standard_date: SYSTEMTIME,
     standard_bias: i32,
     daylight_name: [u16; 32],
     daylight_date: SYSTEMTIME,
     daylight_bias: i32,
-    /// This is the only field we actually need.
-    pub(super) timezone_key_name: [u16; 128],
+    // This is the only field we actually need.
+    pub timezone_key_name: [u16; 128],
     dynamic_daylight_time_disabled: u8,
 }