[MacPorts] #64276: macports will not build ports with Xcode 13.2.1

[MacPorts]

#64276: macports will not build ports with Xcode 13.2.1
--------------------------+--------------------
  Reporter:  AgilentGCMS  |      Owner:  (none)
      Type:  defect       |     Status:  new
  Priority:  Normal       |  Milestone:
 Component:  ports        |    Version:  2.7.1
Resolution:               |   Keywords:
      Port:               |
--------------------------+--------------------

Comment (by AgilentGCMS):

 For example, I tried installing `htop`, with the following error:

 {{{
 $ port install htop
 Warning: The macOS 11 SDK does not appear to be installed. Ports may not
 build correctly.
 Warning: You can install it as part of the Xcode Command Line Tools
 package by running `xcode-select --install'.
 --->  Computing dependencies for htop
 The following dependencies will be installed:
  autoconf
  automake
  gettext
  gettext-runtime
  gettext-tools-libs
  gperf
  libiconv
  libtextstyle
  libtool
  m4
  ncurses
  pkgconfig
  xz
 Continue? [Y/n]:
 Warning: The macOS 11 SDK does not appear to be installed. Ports may not
 build correctly.
 Warning: You can install it as part of the Xcode Command Line Tools
 package by running `xcode-select --install'.
 --->  Configuring gperf
 Error: Failed to configure gperf: consult
 /Users/sbasu1/packages/macports/var/macports/build/_Users_sbasu1_packages_macports_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_devel_gperf/gperf/work/gperf-3.1/config.log
 Error: Failed to configure gperf: configure failure: command execution
 failed
 Error: See
 /Users/sbasu1/packages/macports/var/macports/logs/_Users_sbasu1_packages_macports_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_devel_gperf/gperf/main.log
 for details.
 Error: Follow https://guide.macports.org/#project.tickets if you believe
 there is a bug.
 Error: Processing of port htop failed
 }}}

 I do have an SDK installed,
 {{{
 $ ls -l
 /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/
 total 0
 drwxr-xr-x  7 root  wheel  224 Nov 19 17:25 MacOSX.sdk
 lrwxr-xr-x  1 root  wheel   10 Dec 22 11:13 MacOSX12.1.sdk -> MacOSX.sdk
 }}}
 and I've already run `xcode-select --install`

-- 
Ticket URL: <https://trac.macports.org/ticket/64276#comment:1>
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