Rename libvpx_untrusted->libvpx_nacl. Disable non-portable NaCl build.

libvpx_nacl.gyp

Index: libvpx_nacl.gyp
diff --git a/libvpx_untrusted.gyp b/libvpx_nacl.gyp
similarity index 81%
rename from libvpx_untrusted.gyp
rename to libvpx_nacl.gyp
index 32b3e50b9ecd031e67e7c3e60816c545bf3d16a5..adfc51fccc0bab973dc003de8c5f3b41f946848e 100644
--- a/libvpx_untrusted.gyp
+++ b/libvpx_nacl.gyp
@@ -11,12 +11,12 @@
   ],
   'targets': [
     {
-      'target_name': 'libvpx_untrusted',
+      'target_name': 'libvpx_nacl',
       'type': 'none',
       'variables': {
-        'nlib_target': 'libvpx_untrusted.a',
-        'build_glibc': 1,
-        'build_newlib': 1,
+        'nlib_target': 'libvpx_nacl.a',
+        'build_glibc': 0,
+        'build_newlib': 0,
         'build_pnacl_newlib': 1,
       },
       'dependencies': [
@@ -31,6 +31,6 @@
         '<(libvpx_source)/vp8/encoder',
       ],
       'includes': ['libvpx_srcs_nacl.gypi', ],
-    },  # end of target 'libvpx_untrusted'
+    },  # end of target 'libvpx_nacl'
   ],
 }