Determining if the NOTE_TRUNCATE exist failed with the following output: Change Dir: /home/thomas/autobuild/instance-1/output-1/build/zeek-4.1.1/buildroot-build/libkqueue-build/CMakeFiles/CMakeTmp Run Build Command(s):/usr/bin/make -f Makefile cmTC_b9178/fast && make[1]: Entering directory '/home/thomas/autobuild/instance-1/output-1/build/zeek-4.1.1/buildroot-build/libkqueue-build/CMakeFiles/CMakeTmp' /usr/bin/make -f CMakeFiles/cmTC_b9178.dir/build.make CMakeFiles/cmTC_b9178.dir/build make[2]: Entering directory '/home/thomas/autobuild/instance-1/output-1/build/zeek-4.1.1/buildroot-build/libkqueue-build/CMakeFiles/CMakeTmp' Building C object CMakeFiles/cmTC_b9178.dir/CheckSymbolExists.c.o /home/thomas/autobuild/instance-1/output-1/host/bin/i686-linux-gcc --sysroot=/home/thomas/autobuild/instance-1/output-1/host/i686-buildroot-linux-gnu/sysroot -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -O3 -g0 -D_FORTIFY_SOURCE=2 -fPIE -o CMakeFiles/cmTC_b9178.dir/CheckSymbolExists.c.o -c /home/thomas/autobuild/instance-1/output-1/build/zeek-4.1.1/buildroot-build/libkqueue-build/CMakeFiles/CMakeTmp/CheckSymbolExists.c /home/thomas/autobuild/instance-1/output-1/build/zeek-4.1.1/buildroot-build/libkqueue-build/CMakeFiles/CMakeTmp/CheckSymbolExists.c:2:10: fatal error: sys/event.h: No such file or directory 2 | #include | ^~~~~~~~~~~~~ compilation terminated. make[2]: *** [CMakeFiles/cmTC_b9178.dir/build.make:78: CMakeFiles/cmTC_b9178.dir/CheckSymbolExists.c.o] Error 1 make[2]: Leaving directory '/home/thomas/autobuild/instance-1/output-1/build/zeek-4.1.1/buildroot-build/libkqueue-build/CMakeFiles/CMakeTmp' make[1]: *** [Makefile:127: cmTC_b9178/fast] Error 2 make[1]: Leaving directory '/home/thomas/autobuild/instance-1/output-1/build/zeek-4.1.1/buildroot-build/libkqueue-build/CMakeFiles/CMakeTmp' File /home/thomas/autobuild/instance-1/output-1/build/zeek-4.1.1/buildroot-build/libkqueue-build/CMakeFiles/CMakeTmp/CheckSymbolExists.c: /* */ #include int main(int argc, char** argv) { (void)argv; #ifndef NOTE_TRUNCATE return ((int*)(&NOTE_TRUNCATE))[argc]; #else (void)argc; return 0; #endif }