Determining if the function sin exists failed with the following output: Change Dir: /var/tmp/portage/sci-libs/mathgl-2.4.1/work/mathgl-2.4.1_build/CMakeFiles/CMakeTmp Run Build Command(s):/usr/bin/gmake cmTC_02a2e/fast && /usr/bin/gmake -f CMakeFiles/cmTC_02a2e.dir/build.make CMakeFiles/cmTC_02a2e.dir/build gmake[1]: Entering directory '/var/tmp/portage/sci-libs/mathgl-2.4.1/work/mathgl-2.4.1_build/CMakeFiles/CMakeTmp' Building C object CMakeFiles/cmTC_02a2e.dir/CheckFunctionExists.c.o /usr/bin/x86_64-pc-linux-gnu-gcc -DNDEBUG -O2 -pipe -march=native -DCHECK_FUNCTION_EXISTS=sin -o CMakeFiles/cmTC_02a2e.dir/CheckFunctionExists.c.o -c /usr/share/cmake/Modules/CheckFunctionExists.c : warning: conflicting types for built-in function ‘sin’; expected ‘double(double)’ [-Wbuiltin-declaration-mismatch] /usr/share/cmake/Modules/CheckFunctionExists.c:7:3: note: in expansion of macro ‘CHECK_FUNCTION_EXISTS’ 7 | CHECK_FUNCTION_EXISTS(void); | ^~~~~~~~~~~~~~~~~~~~~ /usr/share/cmake/Modules/CheckFunctionExists.c:1:1: note: ‘sin’ is declared in header ‘’ +++ |+#include 1 | #ifdef CHECK_FUNCTION_EXISTS Linking C executable cmTC_02a2e /usr/bin/cmake -E cmake_link_script CMakeFiles/cmTC_02a2e.dir/link.txt --verbose=1 /usr/bin/x86_64-pc-linux-gnu-gcc -O2 -pipe -march=native -DCHECK_FUNCTION_EXISTS=sin -Wl,-O1 -Wl,--as-needed -rdynamic CMakeFiles/cmTC_02a2e.dir/CheckFunctionExists.c.o -o cmTC_02a2e /usr/lib/gcc/x86_64-pc-linux-gnu/9.2.0/../../../../x86_64-pc-linux-gnu/bin/ld: CMakeFiles/cmTC_02a2e.dir/CheckFunctionExists.c.o: in function `main': CheckFunctionExists.c:(.text.startup+0xc): undefined reference to `sin' collect2: error: ld returned 1 exit status gmake[1]: *** [CMakeFiles/cmTC_02a2e.dir/build.make:87: cmTC_02a2e] Error 1 gmake[1]: Leaving directory '/var/tmp/portage/sci-libs/mathgl-2.4.1/work/mathgl-2.4.1_build/CMakeFiles/CMakeTmp' gmake: *** [Makefile:121: cmTC_02a2e/fast] Error 2 Performing C++ SOURCE FILE Test MGL_HAVE_C99_COMPLEX failed with the following output: Change Dir: /var/tmp/portage/sci-libs/mathgl-2.4.1/work/mathgl-2.4.1_build/CMakeFiles/CMakeTmp Run Build Command(s):/usr/bin/gmake cmTC_4b9a1/fast && /usr/bin/gmake -f CMakeFiles/cmTC_4b9a1.dir/build.make CMakeFiles/cmTC_4b9a1.dir/build gmake[1]: Entering directory '/var/tmp/portage/sci-libs/mathgl-2.4.1/work/mathgl-2.4.1_build/CMakeFiles/CMakeTmp' Building CXX object CMakeFiles/cmTC_4b9a1.dir/src.cxx.o /usr/bin/x86_64-pc-linux-gnu-g++ -DNDEBUG -O2 -pipe -march=native -DMGL_HAVE_C99_COMPLEX -o CMakeFiles/cmTC_4b9a1.dir/src.cxx.o -c /var/tmp/portage/sci-libs/mathgl-2.4.1/work/mathgl-2.4.1_build/CMakeFiles/CMakeTmp/src.cxx /var/tmp/portage/sci-libs/mathgl-2.4.1/work/mathgl-2.4.1_build/CMakeFiles/CMakeTmp/src.cxx: In function ‘int main(int, char**)’: /var/tmp/portage/sci-libs/mathgl-2.4.1/work/mathgl-2.4.1_build/CMakeFiles/CMakeTmp/src.cxx:5:19: error: unable to find numeric literal operator ‘operator""i’ 5 | double _Complex i=1.0i; | ^~~~ /var/tmp/portage/sci-libs/mathgl-2.4.1/work/mathgl-2.4.1_build/CMakeFiles/CMakeTmp/src.cxx:5:19: note: add ‘using namespace std::complex_literals’ (from ) to enable the C++14 user-defined literal suffixes /var/tmp/portage/sci-libs/mathgl-2.4.1/work/mathgl-2.4.1_build/CMakeFiles/CMakeTmp/src.cxx:5:19: note: or use ‘j’ instead of ‘i’ for the GNU built-in suffix gmake[1]: *** [CMakeFiles/cmTC_4b9a1.dir/build.make:66: CMakeFiles/cmTC_4b9a1.dir/src.cxx.o] Error 1 gmake[1]: Leaving directory '/var/tmp/portage/sci-libs/mathgl-2.4.1/work/mathgl-2.4.1_build/CMakeFiles/CMakeTmp' gmake: *** [Makefile:121: cmTC_4b9a1/fast] Error 2 Source file was: #include #include int main(int argc, char *args[]) {std::complex c(2.0, 1.0); double _Complex i=1.0i; double _Complex *a = reinterpret_cast(&c); std::complex b(*a);return 0;}