Merge 6800:7180 from the bleeding edge branch to the experimental/gc branch.

src/SConscript

Index: src/SConscript
===================================================================
--- src/SConscript	(revision 7180)
+++ src/SConscript	(working copy)
@@ -155,6 +155,7 @@
     arm/jump-target-arm.cc
     arm/lithium-arm.cc
     arm/lithium-codegen-arm.cc
+    arm/lithium-gap-resolver-arm.cc
     arm/macro-assembler-arm.cc
     arm/regexp-macro-assembler-arm.cc
     arm/register-allocator-arm.cc
@@ -235,6 +236,7 @@
   'os:android': ['platform-linux.cc', 'platform-posix.cc'],
   'os:macos':   ['platform-macos.cc', 'platform-posix.cc'],
   'os:solaris': ['platform-solaris.cc', 'platform-posix.cc'],
+  'os:cygwin':  ['platform-cygwin.cc', 'platform-posix.cc'],
   'os:nullos':  ['platform-nullos.cc'],
   'os:win32':   ['platform-win32.cc'],
   'mode:release': [],
@@ -266,6 +268,9 @@
   'os:solaris': [
     'd8-posix.cc'
   ],
+  'os:cygwin': [
+    'd8-posix.cc'
+  ],
   'os:win32': [
     'd8-windows.cc'
   ],