undefined reference to `_ULx86_64_step' #4211
Description
On Arch Linux, I get this problem compiling PDAL 2.6.0 against libunwind 1.6.2:
FAILED: bin/pdal_io_sbet_reader_test
: && /usr/bin/c++ -march=x86-64 -mtune=generic -O2 -pipe -fno-plt -fexceptions -Wp,-D_FORTIFY_SOURCE=2 -Wformat -Werror=format-security -fstack-clash-protection -fcf-protection -Wp,-D_GLIBCXX_ASSERTIONS -g -ffile-prefix-map=/build/pdal/src=/usr/src/debug/pdal -flto=auto -Wl,-O1,--sort-common,--as-needed,-z,relro,-z,now -flto=auto test/unit/CMakeFiles/pdal_test_support.dir/Support.cpp.o test/unit/CMakeFiles/pdal_io_sbet_reader_test.dir/io/SbetReaderTest.cpp.o -o bin/pdal_io_sbet_reader_test -Wl,-rpath,/build/pdal/src/PDAL-2.6.0-src/build/lib lib/libpdalcpp.so.16.0.0 lib/libgtest.a && :
/usr/bin/ld: lib/libpdalcpp.so.16.0.0: undefined reference to `_ULx86_64_step'
/usr/bin/ld: lib/libpdalcpp.so.16.0.0: undefined reference to `_Ux86_64_getcontext'
/usr/bin/ld: lib/libpdalcpp.so.16.0.0: undefined reference to `_ULx86_64_init_local'
/usr/bin/ld: lib/libpdalcpp.so.16.0.0: undefined reference to `_ULx86_64_get_proc_name'
/usr/bin/ld: lib/libpdalcpp.so.16.0.0: undefined reference to `_ULx86_64_get_reg'
collect2: error: ld returned 1 exit status
Compiling PDAL 2.5.6 works just fine. Both done using gcc gcc (GCC) 13.2.1 20230801.