Add support for NetBSD (OS = netbsd)

BUG=
R=dpranke@chromium.org, info@bnoordhuis.nl, thechargingvolcano@gmail.com

Review URL: https://codereview.chromium.org/1421073004 .
diff --git a/AUTHORS b/AUTHORS
index 9389ca0..fecf84a 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -9,3 +9,4 @@
 Ryan Norton <rnorton10@gmail.com>
 David J. Sankel <david@sankelsoftware.com>
 Eric N. Vander Weele <ericvw@gmail.com>
+Tom Freudenberg <th.freudenberg@gmail.com>
diff --git a/pylib/gyp/common.py b/pylib/gyp/common.py
index d482a20..256e3f3 100644
--- a/pylib/gyp/common.py
+++ b/pylib/gyp/common.py
@@ -425,6 +425,8 @@
     return 'freebsd'
   if sys.platform.startswith('openbsd'):
     return 'openbsd'
+  if sys.platform.startswith('netbsd'):
+    return 'netbsd'
   if sys.platform.startswith('aix'):
     return 'aix'
 
diff --git a/pylib/gyp/generator/make.py b/pylib/gyp/generator/make.py
index 786b4e0..4fa92f0 100644
--- a/pylib/gyp/generator/make.py
+++ b/pylib/gyp/generator/make.py
@@ -1579,7 +1579,7 @@
       for link_dep in link_deps:
         assert ' ' not in link_dep, (
             "Spaces in alink input filenames not supported (%s)"  % link_dep)
-      if (self.flavor not in ('mac', 'openbsd', 'win') and not
+      if (self.flavor not in ('mac', 'openbsd', 'netbsd', 'win') and not
           self.is_standalone_static_library):
         self.WriteDoCmd([self.output_binary], link_deps, 'alink_thin',
                         part_of_all, postbuilds=postbuilds)
diff --git a/pylib/gyp/generator/ninja.py b/pylib/gyp/generator/ninja.py
index 58be3bf..907542b 100644
--- a/pylib/gyp/generator/ninja.py
+++ b/pylib/gyp/generator/ninja.py
@@ -1271,7 +1271,7 @@
       self.target.type = 'none'
     elif spec['type'] == 'static_library':
       self.target.binary = self.ComputeOutput(spec)
-      if (self.flavor not in ('mac', 'openbsd', 'win') and not
+      if (self.flavor not in ('mac', 'openbsd', 'netbsd', 'win') and not
           self.is_standalone_static_library):
         self.ninja.build(self.target.binary, 'alink_thin', link_deps,
                          order_only=compile_deps)