[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:  assigned
  Priority:  Normal       |  Milestone:
 Component:  ports        |    Version:  2.7.1
Resolution:               |   Keywords:
      Port:  gperf        |
--------------------------+----------------------

Comment (by AgilentGCMS):

 Looking at the `config.log` in more details, I see the following block
 where the CLT version is being checked:
 {{{
 configure:1936: checking for gcc
 configure:1963: result: /usr/bin/clang
 configure:2192: checking for C compiler version
 configure:2201: /usr/bin/clang --version >&5
 Apple clang version 11.0.3 (clang-1103.0.32.29)
 Target: x86_64-apple-darwin20.6.0
 Thread model: posix
 InstalledDir: /Library/Developer/CommandLineTools/usr/bin
 }}}
 However, there's an inconsistency. If port simply used `/usr/bin/clang`,
 it would be fine.
 {{{
 $ which clang
 /usr/bin/clang
 $ `which clang` --version
 Apple clang version 13.0.0 (clang-1300.0.29.30)
 Target: x86_64-apple-darwin20.6.0
 Thread model: posix
 InstalledDir:
 /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin
 }}}
 Instead, it uses an older version of `clang`
 {{{
 $ /Library/Developer/CommandLineTools/usr/bin/clang --version
 Apple clang version 11.0.3 (clang-1103.0.32.29)
 Target: x86_64-apple-darwin20.6.0
 Thread model: posix
 InstalledDir: /Library/Developer/CommandLineTools/usr/bin
 }}}
 I have no idea why that older version is there. Now the question is: Why
 does macports use that older version, when (according to the configure
 output) it found `/usr/bin/clang`, which **should** point it to the newer
 version of `clang`?

-- 
Ticket URL: <https://trac.macports.org/ticket/64276#comment:15>
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