GN

What we've got here is a little GN MVP.  It's lacking any knobs and doesn't yet build anything but libskia, zlib, libpng, and libjpeg-turbo.  I've been hopping back and forth between Linux at work and Mac at home.  These seem to be at least partially working, enough to build and run cmake/example.cpp.

The xcode backend seems to work.  From here, we can start exploring how to handle other backends (cmake,Android make, Google3).  There are a couple things I want to try:
  - add another backend like vs or xcode to GN directly
  - intercept via a custom toolchain
  - reverse from ninja -t commands
That last option seems kind of fun.

This tries to piggyback on Chrome's GN setup as much as possible.  Chrome's got quite a lot figured out, and we're basically required to do this if we want to have a single GN build system shareable by Chrome, our bots, and other clients.

This pulls in some new DEPS:
   - build: Chrome's GN configuration, and much more
   - buildtools: hashes for gn binary, pulled via hooks
   - tools/clang: hashes for Chrome's clang, pulled via hooks into third_party/llvm-build
It additionally symlinks tools/gyp to third_party/externals/gyp.  GN pulls some stuff from tools/gyp on Mac.

Have not yet tried building for Windows, Android, or iOS.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2087593002

Review-Url: https://codereview.chromium.org/2087593002

1 files changed, 5 insertions, 0 deletions

diff --git a/.gitignore b/.gitignore
index 9fb5a30db8..ad2470efa9 100644
--- a/.gitignore
+++ b/.gitignore
@@ -30,3 +30,8 @@ third_party/externals
 tools/skp/page_sets/data/*.json
 tools/skp/page_sets/data/*.wpr
 xcodebuild
+
+build
+buildtools
+tools/clang
+third_party/llvm-build