[MacPorts] #68345: librdkafka @2.2.0_0: building fails with Clang fails due to unused -stdlib flag

[MacPorts]

#68345: librdkafka @2.2.0_0: building fails with Clang fails due to unused -stdlib
flag
---------------------+------------------------
 Reporter:  zbaylin  |      Owner:  (none)
     Type:  defect   |     Status:  new
 Priority:  Normal   |  Milestone:
Component:  ports    |    Version:
 Keywords:           |       Port:  librdkafka
---------------------+------------------------
 When installing librdkafka, the build step fails because the `-stdlib`
 flag is unused by Clang, and `-Werror` and `-Wunused-command-line-
 argument` are enabled.

 Building with `configure.cxx_stdlib=""` succeeds, since the flag is
 conditionally set here: https://github.com/macports/macports-
 ports/blob/4fbdb7680519077095eaa3128d3d28b3a0fec25e/net/librdkafka/Portfile#L29-L31

 This may be an issue with the new version of Clang included in macOS 14
 (Sonoma).

 Below is a relevant part of the log:

 {{{
 /usr/bin/clang -pipe -Os
 -isysroot/Library/Developer/CommandLineTools/SDKs/MacOSX14.sdk -arch arm64
 -I/opt/local/include
 -isysroot/Library/Developer/CommandLineTools/SDKs/MacOSX14.sdk -g -O2
 -Wall -Wsign-compare -Wfloat-equal -Wpointer-arith -Wcast-align -Wall
 -Werror _mkltmpuw2ulX.c -o _mkltmpuw2ulX.c.o  -L../src -L/opt/local/lib
 -Wl,-headerpad_max_install_names -stdlib=libc++
 -Wl,-syslibroot,/Library/Developer/CommandLineTools/SDKs/MacOSX14.sdk
 -arch arm64 -lcurl :
 clang: error: argument unused during compilation: '-stdlib=libc++'
 [-Werror,-Wunused-command-line-argument]
 }}}

-- 
Ticket URL: <https://trac.macports.org/ticket/68345>
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