gyp: specialize node.d for freebsd

`node.d` should use `psinfo.d` instead of `procfs.d` and have statically
defined architecture on FreeBSD.

tools/specialize_node_d.py

@@ -0,0 +1,32 @@
+#!/usr/bin/env python
+
+#
+# specialize_node_d.py output_file src/node.d flavor arch
+#
+# Specialize node.d for given flavor (`freebsd`) and arch (`x64` or `ia32`)
+#
+
+import re
+import subprocess
+import sys
+import errno
+
+if len(sys.argv) != 5:
+  print "usage: specialize_node_d.py outfile src/node.d flavor arch"
+  sys.exit(2);
+
+outfile = file(sys.argv[1], 'w');
+infile = file(sys.argv[2], 'r');
+flavor = sys.argv[3];
+arch = sys.argv[4];
+
+model = r'curpsinfo->pr_dmodel == PR_MODEL_ILP32'
+
+for line in infile:
+  if flavor == 'freebsd':
+    line = re.sub('procfs.d', 'psinfo.d', line);
+    if arch == 'x64':
+      line = re.sub(model, '0', line);
+    else:
+      line = re.sub(model, '1', line);
+  outfile.write(line);