Add windows builds to CI

This commit adds a Windows build to CI now that upstream has a MinGW
build as well.

Closes bytecodealliance#3

Author: alexcrichton

.github/workflows/main.yml

@@ -12,8 +12,9 @@ jobs:
   build:
     runs-on: ${{ matrix.os }}
     strategy:
+      fail-fast: false
       matrix:
-        os: [ubuntu-latest, macos-latest]
+        os: [ubuntu-latest, macos-latest, windows-latest]
         go: ['1.14']
     steps:
     - uses: actions/checkout@v2

ci/download-wasmtime.py

@@ -11,6 +11,7 @@
 import glob
 
 urls = [
+    ['wasmtime-dev-x86_64-mingw-c-api.zip', 'windows-x86_64'],
     ['wasmtime-dev-x86_64-linux-c-api.tar.xz', 'linux-x86_64'],
     ['wasmtime-dev-x86_64-macos-c-api.tar.xz', 'macos-x86_64'],
 ]
@@ -31,8 +32,12 @@
     with urllib.request.urlopen(url) as f:
         contents = f.read()
 
-    t = tarfile.open(fileobj=io.BytesIO(contents))
-    t.extractall()
+    if filename.endswith('.zip'):
+        z = zipfile.ZipFile(file=io.BytesIO(contents))
+        z.extractall()
+    else:
+        t = tarfile.open(fileobj=io.BytesIO(contents))
+        t.extractall()
 
     src = filename.replace('.zip', '').replace('.tar.xz', '')
     if i == 0:

ffi.go

@@ -2,8 +2,11 @@ package wasmtime
 
 // #cgo CFLAGS:-I${SRCDIR}/build/include
 // #cgo !windows LDFLAGS:-lwasmtime -lm -ldl
+// #cgo windows CFLAGS:-DWASM_API_EXTERN= -DWASI_API_EXTERN=
+// #cgo windows LDFLAGS:-lwasmtime -luserenv -lole32 -lntdll -lws2_32 -lkernel32
 // #cgo linux,amd64 LDFLAGS:-L${SRCDIR}/build/linux-x86_64
 // #cgo darwin,amd64 LDFLAGS:-L${SRCDIR}/build/macos-x86_64
+// #cgo windows,amd64 LDFLAGS:-L${SRCDIR}/build/windows-x86_64
 // #include <wasm.h>
 import "C"
 import "runtime"