ci: fix Windows builds

Equivalent of argotorg/hevm#738

Author: elopez

.github/scripts/install-libff.sh

@@ -35,9 +35,14 @@ if [ "$HOST_OS" = "Linux" ] && [ "$(uname -m)" = "aarch64" ]; then
 fi
 
 if [ "$HOST_OS" = "Windows" ]; then
-  ARGS+=("-G" "Ninja")
+  ARGS+=("-G" "Ninja" "-DCMAKE_TOOLCHAIN_FILE=$PWD/../.github/scripts/windows-ghc-toolchain.cmake")
   sed -i 's/find_library(GMP_LIBRARY gmp)/find_library(GMP_LIBRARY NAMES libgmp.a)/' CMakeLists.txt
 
+  # This ends up causing the system headers to be included with -I and
+  # thus they override the GHC mingw compiler ones. So this removes it
+  # and re-adds the include with idirafter via the toolchain file
+  sed -i '/INCLUDE_DIRECTORIES.*OPENSSL_INCLUDE_DIR/d' CMakeLists.txt
+
   # Apply windows-specific libff patch carried by hevm
   curl -fsSL https://raw.githubusercontent.com/ethereum/hevm/1abe4c79eeada928acc279b631c48eeb2a1376c2/.github/scripts/libff.patch | patch -p1
 fi

.github/scripts/windows-ghc-toolchain.cmake

@@ -0,0 +1,12 @@
+set(CMAKE_SYSTEM_NAME Windows)
+
+set(CMAKE_C_COMPILER "$ENV{HASKELL_MINGW_PATH}/bin/cc.exe")
+set(CMAKE_CXX_COMPILER "$ENV{HASKELL_MINGW_PATH}/bin/c++.exe")
+
+set(CMAKE_C_FLAGS "-idirafter $ENV{SYSTEM_MINGW_PATH}/include")
+set(CMAKE_CXX_FLAGS "-idirafter $ENV{SYSTEM_MINGW_PATH}/include")
+
+set(CMAKE_FIND_ROOT_PATH "$ENV{HASKELL_MINGW_PATH}")
+set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM BOTH)
+set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY BOTH)
+set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE BOTH)

.github/workflows/ci.yml

@@ -40,6 +40,7 @@ jobs:
       - name: Get Packages (Windows)
         uses: msys2/setup-msys2@v2
         if: runner.os == 'Windows'
+        id: msys2
         with:
           msystem: CLANG64
           path-type: minimal
@@ -104,11 +105,16 @@ jobs:
         if: runner.os == 'Windows'
         run: |
           HASKELL_PATHS="$(cygpath -u "$GHC_PATH"):$(cygpath -u "$CABAL_PATH"):$(cygpath -u "$STACK_PATH")"
+          HASKELL_MINGW_PATH="$(cygpath -u "$GHC_PATH/../mingw")"
+          SYSTEM_MINGW_PATH="$(cygpath -m "$MSYS2_LOCATION/$MSYSTEM")"
           echo "HASKELL_PATHS=$HASKELL_PATHS" >> "$GITHUB_ENV"
+          echo "HASKELL_MINGW_PATH=$HASKELL_MINGW_PATH" >> "$GITHUB_ENV"
+          echo "SYSTEM_MINGW_PATH=$SYSTEM_MINGW_PATH" >> "$GITHUB_ENV"
         env:
           GHC_PATH: ${{ steps.stack.outputs.ghc-path }}
           CABAL_PATH: ${{ steps.stack.outputs.cabal-path }}
           STACK_PATH: ${{ steps.stack.outputs.stack-path }}
+          MSYS2_LOCATION: ${{ steps.msys2.outputs.msys2-location }}
 
       - name: Checkout
         uses: actions/checkout@v4
@@ -140,7 +146,7 @@ jobs:
       - name: Build Libraries
         run: |
           if [ "$HOST_OS" = "Windows" ]; then
-            export PATH="$(cygpath -u "$GHC_BIN_PATH/../mingw/bin"):$PATH"
+            export PATH="$(cygpath -u "$HASKELL_MINGW_PATH/bin"):$PATH"
           fi
           .github/scripts/install-libsecp256k1.sh
           .github/scripts/install-libff.sh