c3-lang/libffi

diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 76616bd..32befbc 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -344,6 +344,7 @@ jobs:
       - name: Detect tools
         run: |
           $(cygpath $RUNNER_WORKSPACE)/libffi/.ci/msvs-detect --arch=${{ matrix.arch }} --with-assembler
+        shell: C:\tools\cygwin\bin\bash.exe --login --norc -eo pipefail -o igncr '{0}'
 
       - name: Build and test
         run: |