Build fails on NetBSD 11.0 RC7 using GCC 15.2 #326

$ cmake -B build -DCMAKE_CXX_COMPILER="/usr/pkg/gcc15/bin/g++"
-- The CXX compiler identification is GNU 15.2.0
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: /usr/pkg/gcc15/bin/g++ - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Performing Test CMAKE_HAVE_LIBC_PTHREAD
-- Performing Test CMAKE_HAVE_LIBC_PTHREAD - Failed
-- Looking for pthread_create in pthreads
-- Looking for pthread_create in pthreads - not found
-- Looking for pthread_create in pthread
-- Looking for pthread_create in pthread - found
-- Found Threads: TRUE
-- Performing Test HAVE_PTHREAD_GETNAME_NP
-- Performing Test HAVE_PTHREAD_GETNAME_NP - Success
-- Performing Test HAVE_PTHREAD_THREADID_NP
-- Performing Test HAVE_PTHREAD_THREADID_NP - Failed
-- Performing Test HAVE_PTHREAD_GETTHREADID_NP
-- Performing Test HAVE_PTHREAD_GETTHREADID_NP - Failed
-- Configuring done (1.1s)
-- Generating done (0.1s)
-- Build files have been written to: /home/hebasto/dev/libmultiprocess/build
$ cmake --build build               
[ 14%] Building CXX object CMakeFiles/mputil.dir/src/mp/util.cpp.o
[ 14%] Built target mputil
[ 28%] Compiling Cap'n Proto schema include/mp/proxy.capnp
[ 42%] Building CXX object CMakeFiles/multiprocess.dir/include/mp/proxy.capnp.c++.o
[ 57%] Building CXX object CMakeFiles/multiprocess.dir/src/mp/proxy.cpp.o
[ 71%] Linking CXX static library libmultiprocess.a
[ 71%] Built target multiprocess
[ 85%] Building CXX object CMakeFiles/mpgen.dir/src/mp/gen.cpp.o
[100%] Linking CXX executable mpgen
/usr/bin/ld: warning: libstdc++.so.9, needed by /usr/pkg/lib/libcapnp-rpc-1.4.0.so, may conflict with libstdc++.so.7
/usr/bin/ld: warning: libstdc++.so.9, needed by /usr/pkg/lib/libcapnp-rpc-1.4.0.so, may conflict with libstdc++.so.7
/usr/bin/ld: CMakeFiles/mpgen.dir/src/mp/gen.cpp.o: in function `kj::Maybe<kj::Exception> kj::runCatchingExceptions<main::{lambda()#1}>(main::{lambda()#1}&&)':
gen.cpp:(.text+0x62f7): undefined reference to `kj::getCaughtExceptionAsKj()'
collect2: error: ld returned 1 exit status
*** Error code 1

Stop.
make[2]: stopped making "CMakeFiles/mpgen.dir/build" in /home/hebasto/dev/libmultiprocess/build
*** Error code 1

Stop.
make[1]: stopped making "all" in /home/hebasto/dev/libmultiprocess/build
*** Error code 1

Stop.
make: stopped making "default_target" in /home/hebasto/dev/libmultiprocess/build

Can you try #327?

Related: #196 (comment).

See https://github.com/capnproto/capnproto/pull/2756.