[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:  closed
  Priority:  Normal              |  Milestone:
 Component:  ports               |    Version:
Resolution:  fixed               |   Keywords:
      Port:  clang-9.0 clang-10  |
---------------------------------+--------------------

Comment (by thermalecology):

 clang-9.0 now builds but when compiling R:

 checking for gcc... /opt/local/bin/clang-mp-9.0
 checking whether the C compiler works... no
 configure: error: in
 `/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_math_R/R/work/R-4.0.3':
 configure: error: C compiler cannot create executables

-- 
Ticket URL: <https://trac.macports.org/ticket/61477#comment:30>
MacPorts <https://www.macports.org/>
Ports system for macOS