[MacPorts] #61839: cmake: Configure failure with MacOS 11.1 and Xcode 12.3

[MacPorts]

#61839: cmake: Configure failure with MacOS 11.1 and Xcode 12.3
--------------------+-----------------------
 Reporter:  mf2k    |      Owner:  michaelld
     Type:  defect  |     Status:  assigned
 Priority:  Normal  |  Milestone:
Component:  ports   |    Version:  2.6.99
 Keywords:          |       Port:  cmake
--------------------+-----------------------
 I'm updated to macOS 11.1 and Xcode 12.3 with the command line tools.

 I'm now seeing the following build error with cmake:
 {{{
 :debug:configure system:  cd "/opt/local/var/macports/build
 /_opt_mports_macports-ports_devel_cmake/cmake/work/cmake-3.19.1" &&
 ./bootstrap --prefix=/opt/local --docdir=share/doc/cmake --parallel=12
 --init=/opt/local/var/macports/build/_opt_mports_macports-
 ports_devel_cmake/cmake/work/cmake-3.19.1/macports.cmake --system-libs
 --no-system-jsoncpp --no-system-librhash --no-qt-gui --
 :info:configure ---------------------------------------------
 :info:configure CMake 3.19.1, Copyright 2000-2020 Kitware, Inc. and
 Contributors
 :info:configure ---------------------------------------------
 :info:configure Error when bootstrapping CMake:
 :info:configure Cannot find appropriate C compiler on this system.
 :info:configure Please specify one using environment variable CC.
 :info:configure See cmake_bootstrap.log for compilers attempted.
 :info:configure ---------------------------------------------
 :info:configure Log of errors: /opt/local/var/macports/build
 /_opt_mports_macports-
 ports_devel_cmake/cmake/work/cmake-3.19.1/Bootstrap.cmk/cmake_bootstrap.log
 }}}

 In the cmake_bootstrap.log it says:
 {{{cmake_bootstrap_64725_test.c:18:10: fatal error: 'stdio.h' file not
 found
 #include <stdio.h>
          ^~~~~~~~~
 1 error generated.
 Test failed to compile
 }}}

 I will attach both logs.

-- 
Ticket URL: <https://trac.macports.org/ticket/61839>
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