Determining if the getpassphrase exist failed with the following output:
Change Dir: /home/giuliobenetti/autobuild/run/instance-2/output-1/build/znc-1.8.2/CMakeFiles/CMakeTmp

Run Build Command(s):/usr/bin/make cmTC_50375/fast && make[1]: Entering directory '/home/giuliobenetti/autobuild/run/instance-2/output-1/build/znc-1.8.2/CMakeFiles/CMakeTmp'
/usr/bin/make  -f CMakeFiles/cmTC_50375.dir/build.make CMakeFiles/cmTC_50375.dir/build
make[2]: Entering directory '/home/giuliobenetti/autobuild/run/instance-2/output-1/build/znc-1.8.2/CMakeFiles/CMakeTmp'
Building CXX object CMakeFiles/cmTC_50375.dir/CheckSymbolExists.cxx.o
/home/giuliobenetti/autobuild/run/instance-2/output-1/host/bin/arm-buildroot-linux-musleabihf-g++ --sysroot=/home/giuliobenetti/autobuild/run/instance-2/output-1/host/arm-buildroot-linux-musleabihf/sysroot    -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -Os -g0 -DNDEBUG   -DNDEBUG   -o CMakeFiles/cmTC_50375.dir/CheckSymbolExists.cxx.o -c /home/giuliobenetti/autobuild/run/instance-2/output-1/build/znc-1.8.2/CMakeFiles/CMakeTmp/CheckSymbolExists.cxx
/home/giuliobenetti/autobuild/run/instance-2/output-1/build/znc-1.8.2/CMakeFiles/CMakeTmp/CheckSymbolExists.cxx: In function 'int main(int, char**)':
/home/giuliobenetti/autobuild/run/instance-2/output-1/build/znc-1.8.2/CMakeFiles/CMakeTmp/CheckSymbolExists.cxx:8:19: error: 'getpassphrase' was not declared in this scope
    8 |   return ((int*)(&getpassphrase))[argc];
      |                   ^~~~~~~~~~~~~
make[2]: *** [CMakeFiles/cmTC_50375.dir/build.make:69: CMakeFiles/cmTC_50375.dir/CheckSymbolExists.cxx.o] Error 1
make[2]: Leaving directory '/home/giuliobenetti/autobuild/run/instance-2/output-1/build/znc-1.8.2/CMakeFiles/CMakeTmp'
make[1]: *** [Makefile:124: cmTC_50375/fast] Error 2
make[1]: Leaving directory '/home/giuliobenetti/autobuild/run/instance-2/output-1/build/znc-1.8.2/CMakeFiles/CMakeTmp'


File /home/giuliobenetti/autobuild/run/instance-2/output-1/build/znc-1.8.2/CMakeFiles/CMakeTmp/CheckSymbolExists.cxx:
/* */
#include <stdlib.h>

int main(int argc, char** argv)
{
  (void)argv;
#ifndef getpassphrase
  return ((int*)(&getpassphrase))[argc];
#else
  (void)argc;
  return 0;
#endif
}