Determining if the strnstr exist failed with the following output: Change Dir: /home/buildroot/autobuild/instance-2/output-1/build/libnetconf2-2.0.24/CMakeFiles/CMakeTmp Run Build Command(s):/usr/bin/make cmTC_28639/fast && make[1]: Entering directory '/home/buildroot/autobuild/instance-2/output-1/build/libnetconf2-2.0.24/CMakeFiles/CMakeTmp' /usr/bin/make -f CMakeFiles/cmTC_28639.dir/build.make CMakeFiles/cmTC_28639.dir/build make[2]: Entering directory '/home/buildroot/autobuild/instance-2/output-1/build/libnetconf2-2.0.24/CMakeFiles/CMakeTmp' Building C object CMakeFiles/cmTC_28639.dir/CheckSymbolExists.c.o /home/buildroot/autobuild/instance-2/output-1/host/bin/arm-buildroot-linux-uclibcgnueabi-gcc --sysroot=/home/buildroot/autobuild/instance-2/output-1/host/arm-buildroot-linux-uclibcgnueabi/sysroot -D_GNU_SOURCE -D_POSIX_C_SOURCE=200809L -D__BSD_VISIBLE=1 -g -O0 -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -Os -g0 -Wall -Wextra -fvisibility=hidden -std=gnu99 -o CMakeFiles/cmTC_28639.dir/CheckSymbolExists.c.o -c /home/buildroot/autobuild/instance-2/output-1/build/libnetconf2-2.0.24/CMakeFiles/CMakeTmp/CheckSymbolExists.c /home/buildroot/autobuild/instance-2/output-1/build/libnetconf2-2.0.24/CMakeFiles/CMakeTmp/CheckSymbolExists.c: In function 'main': /home/buildroot/autobuild/instance-2/output-1/build/libnetconf2-2.0.24/CMakeFiles/CMakeTmp/CheckSymbolExists.c:8:19: error: 'strnstr' undeclared (first use in this function); did you mean 'strstr'? 8 | return ((int*)(&strnstr))[argc]; | ^~~~~~~ | strstr /home/buildroot/autobuild/instance-2/output-1/build/libnetconf2-2.0.24/CMakeFiles/CMakeTmp/CheckSymbolExists.c:8:19: note: each undeclared identifier is reported only once for each function it appears in /home/buildroot/autobuild/instance-2/output-1/build/libnetconf2-2.0.24/CMakeFiles/CMakeTmp/CheckSymbolExists.c:4:14: warning: parameter 'argc' set but not used [-Wunused-but-set-parameter] 4 | int main(int argc, char** argv) | ~~~~^~~~ CMakeFiles/cmTC_28639.dir/build.make:68: recipe for target 'CMakeFiles/cmTC_28639.dir/CheckSymbolExists.c.o' failed make[2]: *** [CMakeFiles/cmTC_28639.dir/CheckSymbolExists.c.o] Error 1 make[2]: Leaving directory '/home/buildroot/autobuild/instance-2/output-1/build/libnetconf2-2.0.24/CMakeFiles/CMakeTmp' Makefile:124: recipe for target 'cmTC_28639/fast' failed make[1]: *** [cmTC_28639/fast] Error 2 make[1]: Leaving directory '/home/buildroot/autobuild/instance-2/output-1/build/libnetconf2-2.0.24/CMakeFiles/CMakeTmp' File /home/buildroot/autobuild/instance-2/output-1/build/libnetconf2-2.0.24/CMakeFiles/CMakeTmp/CheckSymbolExists.c: /* */ #include int main(int argc, char** argv) { (void)argv; #ifndef strnstr return ((int*)(&strnstr))[argc]; #else (void)argc; return 0; #endif }