[MacPorts] #61477: clang-9.0 fails to build on Big Sur macOS 11.0.1 Xcode 12.2

[MacPorts]

#61477: clang-9.0 fails to build on Big Sur macOS 11.0.1 Xcode 12.2
------------------------+----------------------
  Reporter:  jhoyt4     |      Owner:  kencu
      Type:  defect     |     Status:  assigned
  Priority:  Normal     |  Milestone:
 Component:  ports      |    Version:
Resolution:             |   Keywords:
      Port:  clang-9.0  |
------------------------+----------------------

Comment (by kencu):

 Replying to [comment:2 jhoyt4]:
 > it's a dependency for qt5

 not on my catalina system it isn't.

 Can we figure out what is pulling in an open-source clang compiler on your
 Big Sur system?

 Here is what I see on Catalina:

 {{{
 % port rdeps qt5-qtbase
 The following ports are dependencies of qt5-qtbase @5.14.2_1+openssl:
   xz
     libiconv
       gperf
     gettext
       ncurses
   pkgconfig
   gawk
   zlib
   libpng
   jpeg
   freetype
     brotli
       cmake
         libcxx
         curl
           libidn2
             autoconf
             automake
             libtool
               xattr
                 unzip
             libunistring
               perl5
                 perl5.28
                   db48
                   gdbm
                     readline
               texinfo
                 help2man
                   p5.28-locale-gettext
                 perl5.30
           libpsl
             python38
               bzip2
               expat
               libedit
               libffi
                 expect
                   tcl
                 dejagnu
               openssl
               sqlite3
               python_select
               python3_select
             glib2
               libxml2
                 icu
               pcre
           curl-ca-bundle
         libarchive
           lzo2
           lz4
           zstd
         libuv
   dbus
   pcre2
   harfbuzz
     cairo
       libpixman
       fontconfig
         ossp-uuid
       xrender
         xorg-libX11
           xorg-xtrans
           xorg-xorgproto
           xorg-util-macros
           xorg-libXdmcp
           xorg-libXau
           xorg-libxcb
             xorg-xcb-proto
             xorg-libpthread-stubs
       xorg-libXext
       xorg-xcb-util
     graphite2
       fonttools
         py38-setuptools
         py38-lxml
           libxslt
         py38-brotli
         py38-zopfli
         py38-unicodedata2
   double-conversion
 }}}

 but perhaps it's some other component you're pulling on

-- 
Ticket URL: <https://trac.macports.org/ticket/61477#comment:5>
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