Fix Darwin compiler name.

Test: None because mac
Bug: None
Change-Id: If5844c790b0a14e8a6a88d1cd89ecbec5670e1f8
Exempt-From-Owner-Approval: build fix
diff --git a/build.py b/build.py
index 0702465..b4b2498 100755
--- a/build.py
+++ b/build.py
@@ -104,7 +104,7 @@
     if host == 'darwin':
         toolchain = ndk.paths.android_path(
             'prebuilts/gcc/darwin-x86/host/i686-apple-darwin-4.2.1')
-        toolchain_prefix = 'x86_64-linux'
+        toolchain_prefix = 'i686-apple-darwin10'
         env['MACOSX_DEPLOYMENT_TARGET'] = '10.6'
     elif host == 'linux':
         toolchain = ndk.paths.android_path(