Enable libjpeg for Windows

This is needed to use skia in Android Studio for Windows.

Test: sdk build
Change-Id: I789c80ed9b2f4bfca4efaa1e2df0e9fe3f8db525
diff --git a/Android.bp b/Android.bp
index f69f64e..d2772ec 100644
--- a/Android.bp
+++ b/Android.bp
@@ -200,6 +200,16 @@
                 "-DMACHO",
             ],
         },
+        windows_x86: {
+            asflags: [
+                "-DWIN32",
+            ],
+        },
+        windows_x86_64: {
+            asflags: [
+                "-DWIN64",
+            ],
+        },
     },
     xom: false,
 }
@@ -214,6 +224,11 @@
     },
     defaults: ["libjpeg-defaults"],
     export_include_dirs: ["."],
+    target: {
+        windows: {
+            enabled: true,
+        },
+    },
 }
 
 // Build static library against the NDK