CI: Test on MSYS2/UCRT64 environment

see: https://www.msys2.org/docs/environments

.github/workflows/run_tests_win_mingw.yml

@@ -6,9 +6,6 @@
 
 name: Run MSYS2, MinGW64-based Tests (Not Visual Studio)
 
-env:
-  CPPFLAGS: "-D_BSD_SOURCE"
-
 on: [pull_request,workflow_dispatch]
 
 concurrency:  
@@ -20,6 +17,9 @@ jobs:
   build-and-test-autotools:
 
     runs-on: windows-latest
+    strategy:
+      matrix:
+        msystem: [ MINGW64, UCRT64] #, CLANG64 ]
     defaults:
       run:
         shell: msys2 {0}
@@ -29,9 +29,10 @@ jobs:
       - uses: actions/checkout@v4
       - uses: msys2/setup-msys2@v2
         with:
-          msystem: MINGW64
+          msystem: ${{ matrix.msystem }}
           update: true
-          install: git mingw-w64-x86_64-toolchain automake libtool autoconf make cmake mingw-w64-x86_64-hdf5 unzip mingw-w64-x86_64-libxml2 mingw-w64-x86_64-zlib
+          pacboy: cc:p autotools:p hdf5:p curl:p libxml2:p zlib:p blosc:p bzip2:p
+          install: diffutils m4 git unzip
 
 ###
 # Configure and build