test-fix: windows compilation

.github/workflows/ci.yaml

@@ -13,15 +13,7 @@ jobs:
           - ubuntu-24.04-arm
           - windows-latest
           - windows-11-arm
-          # - macos-latest
-        cc:
-          - cc
-          - cc
-          - gcc
-          - gcc
-          - cc
-    env:
-        CC: ${{matrix.cc}}
+          - macos-latest
     runs-on: ${{matrix.os}}
     steps:
       - uses: actions/checkout@v5
@@ -50,7 +42,7 @@ jobs:
 
       - run: make -Bj libs
         if: steps.cache-deps.outputs.cache-hit != 'true' && runner.os != 'Windows'
-      - run: make -Bj2 libs # compile fewer cores, to save memory.
+      - run: make -Bj1 libs # compile in single-core mode, to save memory, hopefully
         if: steps.cache-deps.outputs.cache-hit != 'true' && runner.os == 'Windows'
 
       - run: make -j all