Initialize struct flock for AIX with O_LARGEFILE used by Python.

pylib/gyp/flock_tool.py

Index: pylib/gyp/flock_tool.py
diff --git a/pylib/gyp/flock_tool.py b/pylib/gyp/flock_tool.py
index 3e7efff26ea80fbf8b2343231019265c0cfde650..b38d8660f728530cae4369ae32f13019f0596604 100755
--- a/pylib/gyp/flock_tool.py
+++ b/pylib/gyp/flock_tool.py
@@ -40,7 +40,12 @@ class FlockTool(object):
     # with EBADF, that's why we use this F_SETLK
     # hack instead.
     fd = os.open(lockfile, os.O_WRONLY|os.O_NOCTTY|os.O_CREAT, 0666)
-    op = struct.pack('hhllhhl', fcntl.F_WRLCK, 0, 0, 0, 0, 0, 0)
+    if sys.platform.startswith('aix'):
+      # Python on AIX is compiled with LARGEFILE support, which changes the
+      # struct size.
+      op = struct.pack('hhIllqq', fcntl.F_WRLCK, 0, 0, 0, 0, 0, 0)
+    else:
+      op = struct.pack('hhllhhl', fcntl.F_WRLCK, 0, 0, 0, 0, 0, 0)
     fcntl.fcntl(fd, fcntl.F_SETLK, op)
     return subprocess.call(cmd_list)