Fix --help output to note that `export SWIG_FEATURES' is required.

git-svn-id: https://swig.svn.sourceforge.net/svnroot/swig/trunk@10095 626c5289-ae23-0410-ae9c-e8d60b6d4f22

CHANGES.current

@@ -1,6 +1,9 @@
 Version 1.3.32 (in progress)
 ============================
 
+11/09/2007: olly
+	    Fix --help output to note that `export SWIG_FEATURES' is required.
+
 10/29/2007: wsfulton
             [R] Fix seg fault on Windows
             [R] Examples R scripts are now platform independent

Source/Modules/main.cxx

@@ -132,7 +132,8 @@ static const char *usage3 = (const char *) "\
 Options can also be defined using the SWIG_FEATURES environment variable, for example:\n\
 \n\
   $ SWIG_FEATURES=\"-Wall\"\n\
-  $ swig -python interface.i \n\
+  $ export SWIG_FEATURES\n\
+  $ swig -python interface.i\n\
 \n\
 is equivalent to: \n\
 \n\