Work on GN iOS build.

Work on GN iOS build.

Separates out some "SDK" related setup on Mac land Linux like we do on Windows. I'm trying to make the "compiler" BUILD file just compiler warnings and CPU options, and have system library stuff on the platform directories.

This adds the capability for GN to produce GYP files on Mac that vary according
to the GYP generator as well as target-vs-host. I added a bunch of logic to the
GN iOS build to set up stuff accordingly based on my current knowledge of
what's required.

Sadly, this means we now have an 8-way GN build (all combinations of
debug/release, host/target, and xcode/ninja). I did some refactoring of the GYP
code in GN to make this less unreasonable.

I checked that the GYP files look the way I want, but I didn't actually test
the resulting builds yet. There is still likely to be some conditions wrong or
things not being set properly. I'm going to follow up with a second pass based on actual testing.

I believe, however, that with this new GYP generator code in GN, we can express
in the .gn files what we need to do the iOS build.

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=248476

[brettw, 2014-01-29 05:38:58]

The GYP files look like this (showing only the leftmost columns for clarity).

'target_name': 're2',
'product_name': 're2',
'type': 'static_library',
'toolsets': ['target', 'host'],
'configurations': {
  'Debug': {
    'conditions': [['"<(GENERAT
      'target_conditions': [['_
        'defines': [ 'CHROMIUM_
        'include_dirs': [ '<(DE
        'xcode_settings': {
          'ARCHS': [ 'i386' ],
          'OTHER_CFLAGS': [ '-f
          'OTHER_CPLUSPLUSFLAGS
          'CC': '/Users/brettw/
          'LDPLUSPLUS': '/Users
        },
      }, {
        'defines': [ 'CHROMIUM_
        'include_dirs': [ '<(DE
        'xcode_settings': {
          'ARCHS': [ 'i386' ],
          'OTHER_CFLAGS': [ '-f
          'OTHER_CPLUSPLUSFLAGS
          'CC': '/Users/brettw/
          'LDPLUSPLUS': '/Users
        },
      }]],
    }, {
      'target_conditions': [['_
        'defines': [ 'CHROMIUM_
        'include_dirs': [ '<(DE
        'xcode_settings': {
          'ARCHS': [ 'i386' ],
          'OTHER_CFLAGS': [ '-f
          'OTHER_CPLUSPLUSFLAGS
          'CC': '/Users/brettw/
          'LDPLUSPLUS': '/Users
        },
      }, {
        'defines': [ 'CHROMIUM_
        'include_dirs': [ '<(DE
        'xcode_settings': {
          'ARCHS': [ 'i386' ],
          'OTHER_CFLAGS': [ '-f
          'OTHER_CPLUSPLUSFLAGS
          'CC': '/Users/brettw/
          'LDPLUSPLUS': '/Users
        },
      }]],
    }]],
  },
  'Release': {

... same thing as the debug section above...

[Nico, 2014-01-29 18:34:18]

lgtm :-/

https://codereview.chromium.org/149163005/diff/20001/build/config/BUILDCONFIG.gn
File build/config/BUILDCONFIG.gn (right):

https://codereview.chromium.org/149163005/diff/20001/build/config/BUILDCONFIG...
build/config/BUILDCONFIG.gn:85: # generator is xcode.On Mac, you can assume if
this is false that the
Nit: missing space after '.', and I'd probably just say "Can only be true on
iOS" as 2nd sentence

[brettw, 2014-02-03 09:30:02]

The CQ bit was checked by brettw@chromium.org

[commit-bot: I haz the power, 2014-02-03 09:30:15]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/brettw@chromium.org/149163005/240001

[commit-bot: I haz the power, 2014-02-03 12:04:35]

Change committed as 248476

[commit-bot: I haz the power, 2014-02-03 12:04:35]

CQ bit was unchecked on CL. Ignoring.

[commit-bot: I haz the power, 2014-02-03 12:04:43]

CQ bit was unchecked on CL. Ignoring.

[msw, 2014-02-03 20:36:26]

Could this be related to a recent iOS runhooks failure?
http://build.chromium.org/p/chromium.mac/builders/iOS%20Device/builds/16407

Error: Command
/Library/Frameworks/Python.framework/Versions/2.7/Resources/Python.app/Contents/MacOS/python
src/build/gyp_chromium returned non-zero exit status 1 in
/b/build/slave/iOS_Device/build
ERROR at //build/config/ios/ios_sdk.gni:30:5: Could not execute python.
    exec_script("ios_sdk.py", [ _ios_sdk_to_query ], "list lines")
    ^----------
I was trying to execute "python".

[msw, 2014-02-03 21:48:43]

On 2014/02/03 20:36:26, msw wrote:
> Could this be related to a recent iOS runhooks failure?
> http://build.chromium.org/p/chromium.mac/builders/iOS%2520Device/builds/16407
> 
> Error: Command
>
/Library/Frameworks/Python.framework/Versions/2.7/Resources/Python.app/Contents/MacOS/python
> src/build/gyp_chromium returned non-zero exit status 1 in
> /b/build/slave/iOS_Device/build
> ERROR at //build/config/ios/ios_sdk.gni:30:5: Could not execute python.
>     exec_script("ios_sdk.py", [ _ios_sdk_to_query ], "list lines")
>     ^----------
> I was trying to execute "python".

Hmm, gclient hooks passed on the next build; not sure what caused the above
failure.
http://build.chromium.org/p/chromium.mac/buildstatus?builder=iOS%20Device&num...
(feel free to follow up with the apparent flake if you wish)

[brettw, 2014-02-04 03:59:11]

It's not obvious why this code would fail. The script is very simple and just
forwards through to "xcodebuild". I'm going to ignore this for now unless it
pops up again.