The setup of the preprocessor define SVN_SWIG_VERSION was damaged. However, it was scarcely used, so convert the only use to use SWIG_VERSION instead, and remove the remains of SVN_SWIG_VERSION support.
* build/ac-macros/swig.m4: Don't AC_SUBST(SWIG_VERSION). * build/generator/gen_make.py: Don't output a -DSVN_SWIG_VERSION=foo. * build/generator/gen_win.py (WinGeneratorBase.get_win_defines): Remove references to self.swig_defines. (WinGeneratorBase._find_swig): Don't set self.swig_defines. * subversion/bindings/swig/core.i: Standardize the format of number used with SWIG_VERSION. * subversion/bindings/swig/include/apr.swg: Use SWIG_VERSION instead of SVN_SWIG_VERSION.