exp/audio/al: add windows support

Tested on Win64 with mingw-w64 and http://kcat.strangesoft.net/openal-binaries/openal-soft-1.18.2-bin.zip

Change-Id: Iec1bf3c0898310878133dc6d9ecfb8781b410347
GitHub-Last-Rev: a71e8eb2b9046b499e1a1911e55cc2534aff8e71
GitHub-Pull-Request: golang/mobile#18
Reviewed-on: https://go-review.googlesource.com/114003
Reviewed-by: Elias Naur <elias.naur@gmail.com>
diff --git a/exp/audio/al/al.go b/exp/audio/al/al.go
index 342d881..bb7bf84 100644
--- a/exp/audio/al/al.go
+++ b/exp/audio/al/al.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build darwin linux
+// +build darwin linux windows
 
 // Package al provides OpenAL Soft bindings for Go.
 //
diff --git a/exp/audio/al/al_notandroid.go b/exp/audio/al/al_notandroid.go
index 8d8b745..85d3782 100644
--- a/exp/audio/al/al_notandroid.go
+++ b/exp/audio/al/al_notandroid.go
@@ -2,15 +2,17 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build darwin linux,!android
+// +build darwin linux,!android windows
 
 package al
 
 /*
 #cgo darwin   CFLAGS:  -DGOOS_darwin
 #cgo linux    CFLAGS:  -DGOOS_linux
+#cgo windows  CFLAGS:  -DGOOS_windows
 #cgo darwin   LDFLAGS: -framework OpenAL
 #cgo linux    LDFLAGS: -lopenal
+#cgo windows  LDFLAGS: -lOpenAL32
 
 #ifdef GOOS_darwin
 #include <stdlib.h>
@@ -21,6 +23,12 @@
 #include <stdlib.h>
 #include <AL/al.h>  // install on Ubuntu with: sudo apt-get install libopenal-dev
 #endif
+
+#ifdef GOOS_windows
+#include <windows.h>
+#include <stdlib.h>
+#include <AL/al.h>
+#endif
 */
 import "C"
 import "unsafe"
diff --git a/exp/audio/al/alc.go b/exp/audio/al/alc.go
index 2c8137d..e70594c 100644
--- a/exp/audio/al/alc.go
+++ b/exp/audio/al/alc.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build darwin linux
+// +build darwin linux windows
 
 package al
 
diff --git a/exp/audio/al/alc_notandroid.go b/exp/audio/al/alc_notandroid.go
index ff7c59b..cb3d8ee 100644
--- a/exp/audio/al/alc_notandroid.go
+++ b/exp/audio/al/alc_notandroid.go
@@ -2,15 +2,17 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build darwin linux,!android
+// +build darwin linux,!android windows
 
 package al
 
 /*
 #cgo darwin   CFLAGS:  -DGOOS_darwin
 #cgo linux    CFLAGS:  -DGOOS_linux
+#cgo windows  CFLAGS:  -DGOOS_windows
 #cgo darwin   LDFLAGS: -framework OpenAL
 #cgo linux    LDFLAGS: -lopenal
+#cgo windows  LDFLAGS: -lOpenAL32
 
 #ifdef GOOS_darwin
 #include <stdlib.h>
@@ -21,6 +23,12 @@
 #include <stdlib.h>
 #include <AL/alc.h>
 #endif
+
+#ifdef GOOS_windows
+#include <windows.h>
+#include <stdlib.h>
+#include <AL/alc.h>
+#endif
 */
 import "C"
 import "unsafe"
diff --git a/exp/audio/al/const.go b/exp/audio/al/const.go
index 8c2fc2f..c8a1cdc 100644
--- a/exp/audio/al/const.go
+++ b/exp/audio/al/const.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build darwin linux
+// +build darwin linux windows
 
 package al