Following up on r33539, perform some code cleanup in gen_win.py.
Following up on r33539, perform some code cleanup in gen_win.py.

* build/generator/gen_win.py
  (GeneratorBase._find_swig), (GeneratorBase._find_neon), 
  (GeneratorBase._find_apr), (GeneratorBase._find_apr_util),
  (GeneratorBase._find_sqlite):
    Don't compile regexes only used once, and use map() to remove doing
    the same conversion three times.
    
Suggested by: gstein

jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion