How to make Xcode use Clang 17?

Question

On my MacOS Sonoma I installed CLang-17 with the following command:

sudo port install clang-17

the command printed the following:

admin@son Downloads % sudo port install clang-17
Password:
--->  Computing dependencies for clang-17
The following dependencies will be installed:
bzip2
cctools
clang_select
db48
gdbm
gettext-runtime
icu
ld64
ld64-xcode
libcxx
libedit
libffi
libiconv
libomp
libxml2
llvm-17
llvm_select
lz4
ncurses
openssl
openssl3
perl5
perl5.34
readline
xar
xz
zlib
zstd
Continue? [Y/n]:
--->  Fetching archive for libcxx
--->  Attempting to fetch libcxx-5.0.1_5.any_any.noarch.tbz2 from https://cph.dk.packages.macports.org/libcxx
--->  Attempting to fetch libcxx-5.0.1_5.any_any.noarch.tbz2.rmd160 from https://cph.dk.packages.macports.org/libcxx
--->  Installing libcxx @5.0.1_5
--->  Activating libcxx @5.0.1_5
--->  Cleaning libcxx
--->  Fetching archive for libomp
--->  Attempting to fetch libomp-18.1.2_1.darwin_23.x86_64.tbz2 from https://cph.dk.packages.macports.org/libomp
--->  Attempting to fetch libomp-18.1.2_1.darwin_23.x86_64.tbz2.rmd160 from https://cph.dk.packages.macports.org/libomp
--->  Installing libomp @18.1.2_1
--->  Activating libomp @18.1.2_1
--->  Cleaning libomp
--->  Fetching archive for clang_select
--->  Attempting to fetch clang_select-2.3_0.any_any.noarch.tbz2 from https://cph.dk.packages.macports.org/clang_select
--->  Attempting to fetch clang_select-2.3_0.any_any.noarch.tbz2.rmd160 from https://cph.dk.packages.macports.org/clang_select
--->  Installing clang_select @2.3_0
--->  Activating clang_select @2.3_0
--->  Cleaning clang_select
--->  Fetching archive for cctools
--->  Attempting to fetch cctools-949.0.1_3+xcode.darwin_any.noarch.tbz2 from https://cph.dk.packages.macports.org/cctools
--->  Attempting to fetch cctools-949.0.1_3+xcode.darwin_any.noarch.tbz2.rmd160 from https://cph.dk.packages.macports.org/cctools
--->  Installing cctools @949.0.1_3+xcode
--->  Activating cctools @949.0.1_3+xcode
--->  Cleaning cctools
--->  Fetching archive for libiconv
--->  Attempting to fetch libiconv-1.17_0.darwin_23.x86_64.tbz2 from https://cph.dk.packages.macports.org/libiconv
--->  Attempting to fetch libiconv-1.17_0.darwin_23.x86_64.tbz2.rmd160 from https://cph.dk.packages.macports.org/libiconv
--->  Installing libiconv @1.17_0
--->  Activating libiconv @1.17_0
--->  Cleaning libiconv
--->  Fetching archive for icu
--->  Attempting to fetch icu-74.2_0.darwin_23.x86_64.tbz2 from https://cph.dk.packages.macports.org/icu
--->  Attempting to fetch icu-74.2_0.darwin_23.x86_64.tbz2.rmd160 from https://cph.dk.packages.macports.org/icu
--->  Installing icu @74.2_0
--->  Activating icu @74.2_0
--->  Cleaning icu
--->  Fetching archive for zlib
--->  Attempting to fetch zlib-1.3.1_0.darwin_23.x86_64.tbz2 from https://cph.dk.packages.macports.org/zlib
--->  Attempting to fetch zlib-1.3.1_0.darwin_23.x86_64.tbz2.rmd160 from https://cph.dk.packages.macports.org/zlib
--->  Installing zlib @1.3.1_0
--->  Activating zlib @1.3.1_0
--->  Cleaning zlib
--->  Fetching archive for gettext-runtime
--->  Attempting to fetch gettext-runtime-0.22.5_0.darwin_23.x86_64.tbz2 from https://cph.dk.packages.macports.org/gettext-runtime
--->  Attempting to fetch gettext-runtime-0.22.5_0.darwin_23.x86_64.tbz2.rmd160 from https://cph.dk.packages.macports.org/gettext-runtime
--->  Installing gettext-runtime @0.22.5_0
--->  Activating gettext-runtime @0.22.5_0
--->  Cleaning gettext-runtime
--->  Fetching archive for xz
--->  Attempting to fetch xz-5.4.6_0.darwin_23.x86_64.tbz2 from https://cph.dk.packages.macports.org/xz
--->  Attempting to fetch xz-5.4.6_0.darwin_23.x86_64.tbz2.rmd160 from https://cph.dk.packages.macports.org/xz
--->  Installing xz @5.4.6_0
--->  Activating xz @5.4.6_0
--->  Cleaning xz
--->  Fetching archive for libxml2
--->  Attempting to fetch libxml2-2.12.6_0.darwin_23.x86_64.tbz2 from https://cph.dk.packages.macports.org/libxml2
--->  Attempting to fetch libxml2-2.12.6_0.darwin_23.x86_64.tbz2.rmd160 from https://cph.dk.packages.macports.org/libxml2
--->  Installing libxml2 @2.12.6_0
--->  Activating libxml2 @2.12.6_0
--->  Cleaning libxml2
--->  Fetching archive for libffi
--->  Attempting to fetch libffi-3.4.6_1.darwin_23.x86_64.tbz2 from https://cph.dk.packages.macports.org/libffi
--->  Attempting to fetch libffi-3.4.6_1.darwin_23.x86_64.tbz2.rmd160 from https://cph.dk.packages.macports.org/libffi
--->  Installing libffi @3.4.6_1
--->  Activating libffi @3.4.6_1
--->  Cleaning libffi
--->  Fetching archive for ncurses
--->  Attempting to fetch ncurses-6.4_1.darwin_23.x86_64.tbz2 from https://cph.dk.packages.macports.org/ncurses
--->  Attempting to fetch ncurses-6.4_1.darwin_23.x86_64.tbz2.rmd160 from https://cph.dk.packages.macports.org/ncurses
--->  Installing ncurses @6.4_1
--->  Activating ncurses @6.4_1
--->  Cleaning ncurses
--->  Fetching archive for libedit
--->  Attempting to fetch libedit-20230828-3.1_0.darwin_23.x86_64.tbz2 from https://cph.dk.packages.macports.org/libedit
--->  Attempting to fetch libedit-20230828-3.1_0.darwin_23.x86_64.tbz2.rmd160 from https://cph.dk.packages.macports.org/libedit
--->  Installing libedit @20230828-3.1_0
--->  Activating libedit @20230828-3.1_0
--->  Cleaning libedit
--->  Fetching archive for llvm_select
--->  Attempting to fetch llvm_select-2_1.any_any.noarch.tbz2 from https://cph.dk.packages.macports.org/llvm_select
--->  Attempting to fetch llvm_select-2_1.any_any.noarch.tbz2.rmd160 from https://cph.dk.packages.macports.org/llvm_select
--->  Installing llvm_select @2_1
--->  Activating llvm_select @2_1
--->  Cleaning llvm_select
--->  Fetching archive for bzip2
--->  Attempting to fetch bzip2-1.0.8_0.darwin_23.x86_64.tbz2 from https://cph.dk.packages.macports.org/bzip2
--->  Attempting to fetch bzip2-1.0.8_0.darwin_23.x86_64.tbz2.rmd160 from https://cph.dk.packages.macports.org/bzip2
--->  Installing bzip2 @1.0.8_0
--->  Activating bzip2 @1.0.8_0
--->  Cleaning bzip2
--->  Fetching archive for openssl3
--->  Attempting to fetch openssl3-3.2.1_1.darwin_23.x86_64.tbz2 from https://cph.dk.packages.macports.org/openssl3
--->  Attempting to fetch openssl3-3.2.1_1.darwin_23.x86_64.tbz2.rmd160 from https://cph.dk.packages.macports.org/openssl3
--->  Installing openssl3 @3.2.1_1
--->  Activating openssl3 @3.2.1_1
--->  Cleaning openssl3
--->  Fetching archive for openssl
--->  Attempting to fetch openssl-3_17.darwin_23.x86_64.tbz2 from https://cph.dk.packages.macports.org/openssl
--->  Attempting to fetch openssl-3_17.darwin_23.x86_64.tbz2.rmd160 from https://cph.dk.packages.macports.org/openssl
--->  Installing openssl @3_17
--->  Activating openssl @3_17
--->  Cleaning openssl
--->  Fetching archive for xar
--->  Attempting to fetch xar-1.8.0.498_0.darwin_23.x86_64.tbz2 from https://cph.dk.packages.macports.org/xar
--->  Attempting to fetch xar-1.8.0.498_0.darwin_23.x86_64.tbz2.rmd160 from https://cph.dk.packages.macports.org/xar
--->  Installing xar @1.8.0.498_0
--->  Activating xar @1.8.0.498_0
--->  Cleaning xar
--->  Fetching archive for lz4
--->  Attempting to fetch lz4-1.9.4_0.darwin_23.x86_64.tbz2 from https://cph.dk.packages.macports.org/lz4
--->  Attempting to fetch lz4-1.9.4_0.darwin_23.x86_64.tbz2.rmd160 from https://cph.dk.packages.macports.org/lz4
--->  Installing lz4 @1.9.4_0
--->  Activating lz4 @1.9.4_0
--->  Cleaning lz4
--->  Fetching archive for zstd
--->  Attempting to fetch zstd-1.5.6_0.darwin_23.x86_64.tbz2 from https://cph.dk.packages.macports.org/zstd
--->  Attempting to fetch zstd-1.5.6_0.darwin_23.x86_64.tbz2.rmd160 from https://cph.dk.packages.macports.org/zstd
--->  Installing zstd @1.5.6_0
--->  Activating zstd @1.5.6_0
--->  Cleaning zstd
--->  Fetching archive for llvm-17
--->  Attempting to fetch llvm-17-17.0.6_1.darwin_23.x86_64.tbz2 from https://cph.dk.packages.macports.org/llvm-17
--->  Attempting to fetch llvm-17-17.0.6_1.darwin_23.x86_64.tbz2.rmd160 from https://cph.dk.packages.macports.org/llvm-17
--->  Installing llvm-17 @17.0.6_1
--->  Activating llvm-17 @17.0.6_1
--->  Cleaning llvm-17
--->  Fetching archive for ld64-xcode
--->  Attempting to fetch ld64-xcode-2_6.darwin_23.x86_64.tbz2 from https://cph.dk.packages.macports.org/ld64-xcode
--->  Attempting to fetch ld64-xcode-2_6.darwin_23.x86_64.tbz2.rmd160 from https://cph.dk.packages.macports.org/ld64-xcode
--->  Installing ld64-xcode @2_6
--->  Activating ld64-xcode @2_6
--->  Cleaning ld64-xcode
--->  Fetching archive for ld64
--->  Attempting to fetch ld64-3_6+ld64_xcode.darwin_23.x86_64.tbz2 from https://cph.dk.packages.macports.org/ld64
--->  Attempting to fetch ld64-3_6+ld64_xcode.darwin_23.x86_64.tbz2.rmd160 from https://cph.dk.packages.macports.org/ld64
--->  Installing ld64 @3_6+ld64_xcode
--->  Activating ld64 @3_6+ld64_xcode
--->  Cleaning ld64
--->  Fetching archive for db48
--->  Attempting to fetch db48-4.8.30_5.darwin_23.x86_64.tbz2 from https://cph.dk.packages.macports.org/db48
--->  Attempting to fetch db48-4.8.30_5.darwin_23.x86_64.tbz2.rmd160 from https://cph.dk.packages.macports.org/db48
--->  Installing db48 @4.8.30_5
--->  Activating db48 @4.8.30_5
--->  Cleaning db48
--->  Fetching archive for readline
--->  Attempting to fetch readline-8.2.001_0.darwin_23.x86_64.tbz2 from https://cph.dk.packages.macports.org/readline
--->  Attempting to fetch readline-8.2.001_0.darwin_23.x86_64.tbz2.rmd160 from https://cph.dk.packages.macports.org/readline
--->  Installing readline @8.2.001_0
--->  Activating readline @8.2.001_0
--->  Cleaning readline
--->  Fetching archive for gdbm
--->  Attempting to fetch gdbm-1.23_0.darwin_23.x86_64.tbz2 from https://cph.dk.packages.macports.org/gdbm
--->  Attempting to fetch gdbm-1.23_0.darwin_23.x86_64.tbz2.rmd160 from https://cph.dk.packages.macports.org/gdbm
--->  Installing gdbm @1.23_0
--->  Activating gdbm @1.23_0
--->  Cleaning gdbm
--->  Fetching archive for perl5.34
--->  Attempting to fetch perl5.34-5.34.3_0.darwin_23.x86_64.tbz2 from https://cph.dk.packages.macports.org/perl5.34
--->  Attempting to fetch perl5.34-5.34.3_0.darwin_23.x86_64.tbz2.rmd160 from https://cph.dk.packages.macports.org/perl5.34
--->  Installing perl5.34 @5.34.3_0
--->  Activating perl5.34 @5.34.3_0
--->  Cleaning perl5.34
--->  Fetching archive for perl5
--->  Attempting to fetch perl5-5.34.1_0+perl5_34.any_any.noarch.tbz2 from https://cph.dk.packages.macports.org/perl5
--->  Attempting to fetch perl5-5.34.1_0+perl5_34.any_any.noarch.tbz2.rmd160 from https://cph.dk.packages.macports.org/perl5
--->  Installing perl5 @5.34.1_0+perl5_34
--->  Activating perl5 @5.34.1_0+perl5_34
--->  Cleaning perl5
--->  Fetching archive for clang-17
--->  Attempting to fetch clang-17-17.0.6_1+analyzer.darwin_23.x86_64.tbz2 from https://cph.dk.packages.macports.org/clang-17
--->  Attempting to fetch clang-17-17.0.6_1+analyzer.darwin_23.x86_64.tbz2.rmd160 from https://cph.dk.packages.macports.org/clang-17
--->  Installing clang-17 @17.0.6_1+analyzer
--->  Activating clang-17 @17.0.6_1+analyzer
--->  Cleaning clang-17
--->  Updating database of binaries
--->  Scanning binaries for linking errors
--->  No broken files found.
--->  No broken ports found.
--->  Some of the ports you installed have notes:
  db48 has the following notes:
    The Java and Tcl bindings are now provided by the db48-java and
    db48-tcl subports.
  libomp has the following notes:
    To use this OpenMP library:
    * For clang-3.8+, or clang-3.7 with +openmp variant:
        add "-fopenmp" during compilation / linking.
    * For clang-3.7 without +openmp variant, use:
        "-I/opt/local/include/libomp -L/opt/local/lib/libomp -fopenmp"

but clang command still runs Clang-15 previously installed with XCode:

Apple clang version 15.0.0 (clang-1500.3.9.4)
Target: x86_64-apple-darwin23.4.0
Thread model: posix
InstalledDir: /Library/Developer/CommandLineTools/usr/bin

Clang-17 is located in /opt/local/libexec/llvm-17/bin directory:

cd /opt/local/libexec/llvm-17/bin
./clang --version

clang version 17.0.6
Target: x86_64-apple-darwin23.4.0
Thread model: posix
InstalledDir: /opt/local/libexec/llvm-17/bin/.

How do I switch between two Clang versions?

And is it possible to make XCode and CMake work with Clang 17?

Tried

sudo port select --set clang mp-clang-17
Selecting 'mp-clang-17' for 'clang' succeeded. 'mp-clang-17' is now active.

but clang command is still runs Clang 15:

clang --version
Apple clang version 15.0.0 (clang-1500.3.9.4)
Target: x86_64-apple-darwin23.4.0
Thread model: posix
InstalledDir: /Library/Developer/CommandLineTools/usr/bin