Using su as default (set KDESU_USE_SUDO_DEFAULT=On to use sudo)
CMake Warning:
  Manually-specified variables were not used by the project:

    CMAKE_LD_FLAGS
    ECM_MKSPECS_INSTALL_DIR


In file included from /usr/include/errno.h:25,
                 from /var/pisi/kdesu-6.20.0-80/work/kdesu-6.20.0/src/kdesu_stub.c:31:
/usr/include/features.h:199:3: warning: #warning "_BSD_SOURCE and _SVID_SOURCE are deprecated, use _DEFAULT_SOURCE" [-Wcpp]
  199 | # warning "_BSD_SOURCE and _SVID_SOURCE are deprecated, use _DEFAULT_SOURCE"
      |   ^~~~~~~
/var/pisi/kdesu-6.20.0-80/work/kdesu-6.20.0/src/kdesu_stub.c: In function ‘main’:
/var/pisi/kdesu-6.20.0-80/work/kdesu-6.20.0/src/kdesu_stub.c:348:9: warning: ignoring return value of ‘system’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
  348 |         system("kdeinit5 --suicide");
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/var/pisi/kdesu-6.20.0-80/work/kdesu-6.20.0/src/sshprocess.cpp: In member function ‘int KDESu::SshProcess::converseSsh(const char*, int)’:
/var/pisi/kdesu-6.20.0-80/work/kdesu-6.20.0/src/sshprocess.cpp:208:22: warning: ignoring return value of ‘ssize_t write(int, const void*, size_t)’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
  208 |                 write(fd(), password, strlen(password));
      |                 ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/var/pisi/kdesu-6.20.0-80/work/kdesu-6.20.0/src/sshprocess.cpp:209:22: warning: ignoring return value of ‘ssize_t write(int, const void*, size_t)’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
  209 |                 write(fd(), "\n", 1);
      |                 ~~~~~^~~~~~~~~~~~~~~
/var/pisi/kdesu-6.20.0-80/work/kdesu-6.20.0/src/ptyprocess.cpp: In member function ‘void KDESu::PtyProcess::writeLine(const QByteArray&, bool)’:
/var/pisi/kdesu-6.20.0-80/work/kdesu-6.20.0/src/ptyprocess.cpp:254:14: warning: ignoring return value of ‘ssize_t write(int, const void*, size_t)’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
  254 |         write(fd(), line.constData(), line.length());
      |         ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/var/pisi/kdesu-6.20.0-80/work/kdesu-6.20.0/src/ptyprocess.cpp:257:14: warning: ignoring return value of ‘ssize_t write(int, const void*, size_t)’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
  257 |         write(fd(), "\n", 1);
      |         ~~~~~^~~~~~~~~~~~~~~
/var/pisi/kdesu-6.20.0-80/work/kdesu-6.20.0/src/suprocess.cpp: In member function ‘int KDESu::SuProcess::converseSU(const char*)’:
/var/pisi/kdesu-6.20.0-80/work/kdesu-6.20.0/src/suprocess.cpp:275:22: warning: ignoring return value of ‘ssize_t write(int, const void*, size_t)’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
  275 |                 write(fd(), password, strlen(password));
      |                 ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/var/pisi/kdesu-6.20.0-80/work/kdesu-6.20.0/src/suprocess.cpp:276:22: warning: ignoring return value of ‘ssize_t write(int, const void*, size_t)’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
  276 |                 write(fd(), "\n", 1);
      |                 ~~~~~^~~~~~~~~~~~~~~
/var/pisi/kdesu-6.20.0-80/work/kdesu-6.20.0/src/kdesud/kdesud.cpp: In function ‘void sigchld_handler(int)’:
/var/pisi/kdesu-6.20.0-80/work/kdesu-6.20.0/src/kdesud/kdesud.cpp:215:10: warning: ignoring return value of ‘ssize_t write(int, const void*, size_t)’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
  215 |     write(pipeOfDeath[1], &c, 1);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~
/var/pisi/kdesu-6.20.0-80/work/kdesu-6.20.0/src/kdesud/kdesud.cpp: In function ‘int main(int, char**)’:
/var/pisi/kdesu-6.20.0-80/work/kdesu-6.20.0/src/kdesud/kdesud.cpp:418:10: warning: ignoring return value of ‘int pipe2(int*, int)’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
  418 |     pipe2(pipeOfDeath, O_CLOEXEC);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
/var/pisi/kdesu-6.20.0-80/work/kdesu-6.20.0/src/kdesud/kdesud.cpp:476:21: warning: ignoring return value of ‘ssize_t read(int, void*, size_t)’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
  476 |                 read(pipeOfDeath[0], buf, 100);
      |                 ~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~