Patch for ports on 10-current

[Nali Toja]

Doug Barton <dougb at FreeBSD.org> writes:

> http://dougbarton.us/bam.patch
[...]
> +.if ${OSVERSION} >= 1000000 && !defined(NO_AUTOTOOLS_FIX)

Being not limited to GNU_CONFIGURE, is it a feature?

Also, there are a few ports that either set WRKSRC instead of
BUILD_WRKSRC or extract several distfiles. Why not use WRKDIR then?

  # lang/python27, it does not use devel/libffi (ports/146823)
  WRKSRC/../Modules/_ctypes/libffi/configure:    freebsd1*)
  WRKSRC/../Modules/_ctypes/libffi/configure:freebsd1*)