makeqstrdata: print error to stderr.

py/makeqstrdata.py

 import argparse
 import re
+import sys
 
 # codepoint2name is different in Python 2 to Python 3
 import platform
@@ -37,7 +38,7 @@ def do_work(infiles):
                 # verify line is of the correct form
                 match = re.match(r'Q\((.+)\)$', line)
                 if not match:
-                    print('({}:{}) bad qstr format, got {}'.format(infile, line_number, line))
+                    print('({}:{}) bad qstr format, got {}'.format(infile, line_number, line), file=sys.stderr)
                     return False
 
                 # get the qstr value
@@ -68,7 +69,7 @@ def main():
 
     result = do_work(args.files)
     if not result:
-        print('exiting with error code')
+        print('exiting with error code', file=sys.stderr)
         exit(1)
 
 if __name__ == "__main__":