CI: select ucrt64 compiler

MSYS gcc (/usr/bin/gcc) is not the native Windows compiler. Select the
UCRT64 compiler explicitly. Without this, the header guards in endian.h
and types.h do not work.

Signed-off-by: Daniel Wagner <[email protected]>

Author: igaw

.github/workflows/build.yml

@@ -253,11 +253,11 @@ jobs:
           which git
           git --version
           git config --global --add safe.directory "$GITHUB_WORKSPACE"
-          scripts/build.sh -b release -c gcc
+          scripts/build.sh -b release -c /ucrt64/bin/gcc
 
       - uses: actions/upload-artifact@bbbca2ddaa5d8feaa63e36b76fdaad77386f024f # v7.0.0
         if: failure()
         with:
           name: windows-msys2-ucrt64-logs
           path: |
-            .build-ci/meson-logs/*.txt
+            .build-ci/meson-logs/*.txt