libunwind-headers: has a dependency on clang-3.7 etc that it should not have on SnowLeopard

[kencu (Ken)]

libunwind-headers just installs some headers, and has no build phase.

It makes efforts on older systems not to have any dependencies in the Portfile, but these efforts do not appear fruitful.

On a clean install of SnowLeopard:

$ uname -a
Darwin SL2.local 10.8.0 Darwin Kernel Version 10.8.0: Tue Jun  7 16:33:36 PDT 2011; root:xnu-1504.15.3~1/RELEASE_I386 i386

$ port -v
MacPorts 2.6.2

$ port -v installed
No ports are installed.

$ port rdeps libunwind-headers
The following ports are dependencies of libunwind-headers @5.0.1_0:
  xz-bootstrap
    libiconv-bootstrap
      gperf-bootstrap
    gettext-bootstrap
      ncurses-bootstrap
  clang-3.7
    cctools
      libunwind-headers
      llvm-3.4
        libffi
        zlib
        perl5
          perl5.28
            xz
              clang-3.4
                python27-bootstrap
                  pkgconfig-bootstrap
                  bzip2
                  expat
                  openssl
                clang_select
                ld64
                  ld64-127
                    libmacho-headers
              libiconv
                gperf
                  libcxx
              gettext
                ncurses
            db48
            gdbm
              readline
        llvm_select
    llvm-3.7
      libedit
      python27
        pkgconfig
        sqlite3
        python_select
        python2_select

And this dramatically increases the bootstrap load for libcxx of course, which I am working on today.

I will see if I can figure out why this is broken...

[kencu (Ken)]

Fixed. I reset all the conf defaults back to original settings. I think there must have been something in there left over from LibcxxOnOlderSystems to cause this.