Merge pull request #9 from indigoid/windows-logging-fix

Windows logging fix - looks good to me, thanks John

boxmaker.py

@@ -31,14 +31,15 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 '''
 __version__ = "0.86" ### please report bugs, suggestions etc to bugs@twot.eu ###
 
-import sys,inkex,simplestyle,gettext,math
+import os,sys,inkex,simplestyle,gettext,math
 _ = gettext.gettext
 
 def log(text):
-  if 1:
-    f = open('/tmp/boxmaker.log', 'a')
+  if 'SCHROFF_LOG' in os.environ:
+    f = open(os.environ.get('SCHROFF_LOG'), 'a')
     f.write(text + "\n")
 
+
 def drawS(XYstring):         # Draw lines from a list
   name='part'
   style = { 'stroke': '#000000', 'fill': 'none' }