Fix building of SWIG bindings on OS X.
Fix building of SWIG bindings on OS X.

The GNOME Keyring support is not built if we are on DARWIN or Windows.
core.i of SWIG looks for SVN_AUTH_PARAM_GNOME_KEYRING_UNLOCK_PROMPT_FUNC to
determine if GNOME Keyring support should be built.  DARWIN gets defined from
the CPPFLAGS.  However, we were not passing CPPFLAGS to SWIG (which is just a
glorified C Pre-Processor), so the constant we are looking for gets defined in
the SWIG pass and SWIG includes and wraps our helper function.  Then the C
compiler builds core.c and now the keyring support is not included since
we pass CPPFLAGS into the compiler.  Resulting in an error.

* build.conf: Need to pass the CPPFLAGS to SWIG.



git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@1397844 13f79535-47bb-0310-9956-ffa450edef68

YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion