Fix x86 building on Windows with compilers that support multiple target architectures (E.g. Visual Studio 2010 and later)
Fix x86 building on Windows with compilers that support multiple target
architectures (E.g. Visual Studio 2010 and later)

* SConstruct
  - Disable LINKFLAGS variable on Windows as it breaks platform defaults
  - Allow overriding SCons' TARGET_ARCH
  - Use SCons standard support for generating debug info on Windows.
  - Don't use -std=c89 for non c code.
  - Define NDEBUG and DEBUG when appropriate
  - Properly construct Windows dependency paths to install locations.
jandre/serf,jandre/serf,jandre/serf,jandre/serf