[infra] Roll clang to match the version used by Flutter

[infra] Roll clang to match the version used by Flutter

Flutter uses the same clang toolchain as Fuchsia. This CL puts Dart
on that toolchain, as well. This roll should entail no changes to
glibc version requirements on Linux.

The Fuchsia buildtools distribute clang-format with the toolchain
rather than separately, so this CL introduces forwarding scripts
that are copied to the right place under //buildtools.

This CL sets the default for the number of workers in //tools/gn.py
to 1, as the newer GN version fails occasionally when run
concurrently with other invocations.

As Flutter does, this CL uses the clang toolchain to build for
Android. Thus, it is now possible to build for Android on MacOS.

This change is a prerequisite for assembling the SDK in GN
rather than with a python script:

https://codereview.chromium.org/2848943003/

and will be nicer for making prebuilt SDKs for Fuchsia.


Resubmitting this with the following fixes:
1. Rolls further forward to get past a GN bug
2. Fixes the Android build.
3. Style cleanups in gn.py

Committed: https://github.com/dart-lang/sdk/commit/726732dd6b02aa4f8117707071c54004a7c6e815

[zra, 2017-05-04 20:00:30]

zra@google.com changed reviewers:
+ asiva@google.com, whesse@google.com

[zra, 2017-05-07 04:36:37]

TBR

Re-landing during off hours to avoid possible disruptions.

[zra, 2017-05-07 04:45:06]

Description was changed from

==========
[infra] Roll clang to match the version used by Flutter

Flutter uses the same clang toolchain as Fuchsia. This CL puts Dart
on that toolchain, as well. This roll should entail no changes to
glibc version requirements on Linux.

The Fuchsia buildtools distribute clang-format with the toolchain
rather than separately, so this CL introduces forwarding scripts
that are copied to the right place under //buildtools.

This CL sets the default for the number of workers in //tools/gn.py
to 1, as the newer GN version fails occasionally when run
concurrently with other invocations.

As Flutter does, this CL uses the clang toolchain to build for
Android. Thus, it is now possible to build for Android on MacOS.

This change is a prerequisite for assembling the SDK in GN
rather than with a python script:

https://codereview.chromium.org/2848943003/

and will be nicer for making prebuilt SDKs for Fuchsia.


Resubmitting this with the following fixes:
1. Rolls further forward to get past a GN bug
2. Fixes the Android build.
3. Style cleanups in gn.py
==========

to

==========
[infra] Roll clang to match the version used by Flutter

Flutter uses the same clang toolchain as Fuchsia. This CL puts Dart
on that toolchain, as well. This roll should entail no changes to
glibc version requirements on Linux.

The Fuchsia buildtools distribute clang-format with the toolchain
rather than separately, so this CL introduces forwarding scripts
that are copied to the right place under //buildtools.

This CL sets the default for the number of workers in //tools/gn.py
to 1, as the newer GN version fails occasionally when run
concurrently with other invocations.

As Flutter does, this CL uses the clang toolchain to build for
Android. Thus, it is now possible to build for Android on MacOS.

This change is a prerequisite for assembling the SDK in GN
rather than with a python script:

https://codereview.chromium.org/2848943003/

and will be nicer for making prebuilt SDKs for Fuchsia.


Resubmitting this with the following fixes:
1. Rolls further forward to get past a GN bug
2. Fixes the Android build.
3. Style cleanups in gn.py

Committed:
https://github.com/dart-lang/sdk/commit/726732dd6b02aa4f8117707071c54004a7c6e815
==========

[zra, 2017-05-07 04:45:07]

Committed patchset #3 (id:40001) manually as
726732dd6b02aa4f8117707071c54004a7c6e815 (presubmit successful).

[aam, 2017-05-09 01:23:51]

aam@google.com changed reviewers:
+ aam@google.com

[aam, 2017-05-09 01:23:52]

https://codereview.chromium.org/2858873005/diff/40001/tools/buildtools/linux6...
File tools/buildtools/linux64/clang-format (right):

https://codereview.chromium.org/2858873005/diff/40001/tools/buildtools/linux6...
tools/buildtools/linux64/clang-format:12: DART_ROOT =
os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
DART_ROOT here actually points to dart-sdk/sdk/buildtools instead of
dart-sdk/sdk. 
So perhaps these two lines should read 
BUILDTOOlS = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
TOOLCHAIN = os.path.join(BUILDTOOlS, 'toolchain')

[aam, 2017-05-09 01:49:17]

https://codereview.chromium.org/2858873005/diff/40001/tools/buildtools/linux6...
File tools/buildtools/linux64/clang-format (right):

https://codereview.chromium.org/2858873005/diff/40001/tools/buildtools/linux6...
tools/buildtools/linux64/clang-format:1: #!/usr/bin/env python
When invoked via 'git cl format' this script won't be able to find python in the
environment PATH because PATH is reset by git_cl.py
https://chromium.googlesource.com/chromium/tools/depot_tools.git/+/HEAD/git_c...

Easiest fix would be to do #!/usr/bin/python here instead.

[aam, 2017-05-09 01:49:30]

Description was changed from

==========
[infra] Roll clang to match the version used by Flutter

Flutter uses the same clang toolchain as Fuchsia. This CL puts Dart
on that toolchain, as well. This roll should entail no changes to
glibc version requirements on Linux.

The Fuchsia buildtools distribute clang-format with the toolchain
rather than separately, so this CL introduces forwarding scripts
that are copied to the right place under //buildtools.

This CL sets the default for the number of workers in //tools/gn.py
to 1, as the newer GN version fails occasionally when run
concurrently with other invocations.

As Flutter does, this CL uses the clang toolchain to build for
Android. Thus, it is now possible to build for Android on MacOS.

This change is a prerequisite for assembling the SDK in GN
rather than with a python script:

https://codereview.chromium.org/2848943003/

and will be nicer for making prebuilt SDKs for Fuchsia.


Resubmitting this with the following fixes:
1. Rolls further forward to get past a GN bug
2. Fixes the Android build.
3. Style cleanups in gn.py

Committed:
https://github.com/dart-lang/sdk/commit/726732dd6b02aa4f8117707071c54004a7c6e815
==========

to

==========
[infra] Roll clang to match the version used by Flutter

Flutter uses the same clang toolchain as Fuchsia. This CL puts Dart
on that toolchain, as well. This roll should entail no changes to
glibc version requirements on Linux.

The Fuchsia buildtools distribute clang-format with the toolchain
rather than separately, so this CL introduces forwarding scripts
that are copied to the right place under //buildtools.

This CL sets the default for the number of workers in //tools/gn.py
to 1, as the newer GN version fails occasionally when run
concurrently with other invocations.

As Flutter does, this CL uses the clang toolchain to build for
Android. Thus, it is now possible to build for Android on MacOS.

This change is a prerequisite for assembling the SDK in GN
rather than with a python script:

https://codereview.chromium.org/2848943003/

and will be nicer for making prebuilt SDKs for Fuchsia.


Resubmitting this with the following fixes:
1. Rolls further forward to get past a GN bug
2. Fixes the Android build.
3. Style cleanups in gn.py

Committed:
https://github.com/dart-lang/sdk/commit/726732dd6b02aa4f8117707071c54004a7c6e815
==========

[aam, 2017-05-09 01:49:30]

aam@google.com changed reviewers:
- aam@google.com