ci: windows: fix build with secp256k1 0.4.0+

See bitcoin-core/secp256k1#1367

.github/workflows/build.yml

@@ -124,7 +124,7 @@ jobs:
           cabal configure --disable-documentation --enable-executable-static --enable-executable-stripping \
             --extra-include-dirs="$HOME/.local/include" --extra-lib-dirs="$HOME/.local/lib" \
             --extra-include-dirs="D:/a/_temp/msys64/clang64/include" --extra-lib-dirs="D:/a/_temp/msys64/clang64/lib" \
-            --ghc-options=-pgml=D:/a/_temp/msys64/clang64/bin/clang.exe
+            --ghc-options=-pgml=D:/a/_temp/msys64/clang64/bin/clang.exe -fstatic-secp256k1
           cabal build --dry-run
           # The last step generates dist-newstyle/cache/plan.json for the cache key.
 

hevm.cabal

@@ -25,6 +25,11 @@ extra-source-files:
 extra-doc-files:
   CHANGELOG.md
 
+flag static-secp256k1
+  description: Sets flags for compilation with static secp256k1
+  default:     False
+  manual:      True
+
 flag ci
   description: Sets flags for compilation in CI
   default:     False
@@ -111,6 +116,9 @@ library
     Paths_hevm
   autogen-modules:
     Paths_hevm
+  if os(windows) && flag(static-secp256k1)
+    cc-options: -DSECP256K1_STATIC
+    cxx-options: -DSECP256K1_STATIC
   if os(darwin)
     -- https://gitlab.haskell.org/ghc/ghc/-/issues/11829
     ld-options: -Wl,-keep_dwarf_unwind