Top-level wrapper script to do the environment setup.

This sets up $WIX and $LD_PRELOAD before running a Wix .NET executable
via mono, so the user doesn't have to have pre-prepared those
variables (and, in particular, libpreload doesn't uncontrolledly
affect loads of other stuff too).

wrapper.py

@@ -0,0 +1,22 @@
+#!/usr/bin/env python
+
+import sys
+import os
+
+def addtopath(val, varname):
+    newvar = val
+    if varname in os.environ:
+        if val in os.environ[varname].split(":"):
+            return # already there
+        newvar += ":" + os.environ[varname]
+    os.environ[varname] = newvar
+
+scriptname = os.path.basename(sys.argv[0])
+wixdir = os.path.dirname(os.path.abspath(__file__))
+
+addtopath(os.path.join(wixdir, "libpreload.so"), "LD_PRELOAD")
+
+os.environ["WIX"] = wixdir
+
+dotnet_exe = os.path.join(wixdir, scriptname + ".exe")
+os.execvp("/usr/bin/mono", ["mono", dotnet_exe] + sys.argv[1:])