Of course I didn't want to build for Darwin! Duh!

Bug: http://b/111874156
Test: I don't have a Mac
Change-Id: I139ab4d574824c76b6dd0bdda18cc5bd465badaf
diff --git a/Android.bp b/Android.bp
index 9e13c82..82c16a4 100755
--- a/Android.bp
+++ b/Android.bp
@@ -30,6 +30,9 @@
     static_libs: ["libarm-optimized-routines"],
     local_include_dirs: ["math/include"],
     target: {
+        darwin: {
+            enabled: false,
+        },
         linux_bionic: {
             enabled: true,
         },