More CI workflow work.

Also change msvc_random hack to detect MSVC itself, as it turned out
that the Windows CI environment was actually running MinGW.

.github/workflows/build_cmake.yml

@@ -32,6 +32,7 @@ jobs:
       matrix:
         os: [ubuntu-22.04, windows-latest]
         build_type: [Release]
+        # TODO? mingw32 on Windows?
         cpp_compiler: [g++, clang++, cl]
         include:
           - os: ubuntu-22.04
@@ -76,6 +77,9 @@ jobs:
           ref: ${{ github.event.pull_request.head.sha }}
           submodules: true
 
+      - if: matrix.os == 'windows-latest'
+        uses: ilammy/[email protected]
+
       - name: "Create directory '${{ env.VCPKG_DEFAULT_BINARY_CACHE }}'"
         run: mkdir -p $VCPKG_DEFAULT_BINARY_CACHE
         shell: bash

src/hack/msvc_random.h

@@ -8,7 +8,7 @@
 // need in a way that MSVC understands.
 
 // MSVC RANDOM HACK
-#if _WIN32
+#if defined(_MSC_VER)
 #define srand48(x) (srand((unsigned int(x))))
 #define drand48() ((double)rand()/(RAND_MAX+1.0))
 #define srandom(x) (srand((unsigned int)(x)))