add conditional logic for freebsd vs linux

wscript

@@ -1,5 +1,7 @@
 # -*- python -*-
 
+import sys
+
 def set_options(opt):
   opt.tool_options("compiler_cxx")
 
@@ -9,8 +11,13 @@ def configure(conf):
 
 def build(bld):
   obj = bld.new_task_gen("cxx", "shlib", "node_addon")
-  obj.cxxflags = ["-g", "-D_FILE_OFFSET_BITS=64", "-D_LARGEFILE_SOURCE", "-Wall", 
-                  "-I/usr/local/include/tcl8.5" ]
-  obj.ldflags = [ "-ltcl85" ]
+  obj.cxxflags = ["-g", "-D_FILE_OFFSET_BITS=64", "-D_LARGEFILE_SOURCE", "-Wall"]
+
+  if sys.platform.startswith('freebsd'):
+    obj.cxxflags.append("-I/usr/local/include/tcl8.5")
+    obj.ldflags = [ "-ltcl85" ]
+  else:
+    obj.ldflags = [ "-ltcl8.5" ]
+
   obj.target = "nodetcl"
   obj.source = "src/nodetcl.cc"