This CL switches the ia32 and arm64 builds to use clang by default.
The arm build can't be switched at least until we roll clang to
pick up the fix for https://reviews.llvm.org/D34691.
This CL also changes to use the sysroots from wheezy (and jessie
for arm64) by default so that we can be building/testing locally with
the same setup as we are shipping in the SDK.
Change-Id: I09a1907ee7f78c3f4bb8d56ffdbbd6107ed054d9
Reviewed-on: https://dart-review.googlesource.com/25160
Reviewed-by: Ryan Macnak <rmacnak@google.com>
Reviewed-by: Vyacheslav Egorov <vegorov@google.com>
Commit-Queue: Zach Anderson <zra@google.com>
Ryan Macnak