Fix ABI tests on MinGW32

Author: kornelski

.github/workflows/stable.yml

@@ -169,6 +169,13 @@ jobs:
     strategy:
       matrix:
         target: ["x86_64-pc-windows-msvc", "i686-pc-windows-msvc", "x86_64-pc-windows-gnu", "i686-pc-windows-gnu"]
+        include:
+          - target: "i686-pc-windows-gnu"
+            cflags: "-mlong-double-64" # bindgen detects that Rust doesn't support 80-bit long double
+    env:
+      CFLAGS: ${{ matrix.cflags }}
+      CXXFLAGS: ${{ matrix.cflags }}
+      BINDGEN_EXTRA_CLANG_ARGS: ${{ matrix.cflags }}
     # Only run on "pull_request" event for external PRs. This is to avoid
     # duplicate builds for PRs created from internal branches.
     if: github.event_name == 'push' || github.event.pull_request.head.repo.full_name != github.repository