Determining if the function sin exists failed with the following output:
Change Dir: /var/tmp/portage/sci-libs/mathgl-2.4.4/work/mathgl-2.4.4_build/CMakeFiles/CMakeTmp

Run Build Command(s):/usr/bin/ninja cmTC_95326 && [1/2] Building C object CMakeFiles/cmTC_95326.dir/CheckFunctionExists.c.o
<command-line>: 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 ‘<math.h>’
  +++ |+#include <math.h>
    1 | #ifdef CHECK_FUNCTION_EXISTS
[2/2] Linking C executable cmTC_95326
FAILED: cmTC_95326 
: && /usr/bin/x86_64-pc-linux-gnu-gcc -O2 -pipe -march=native -fno-diagnostics-color -DCHECK_FUNCTION_EXISTS=sin -Wl,-O1 -Wl,--as-needed -Wl,--defsym=__gentoo_check_ldflags__=0   -rdynamic CMakeFiles/cmTC_95326.dir/CheckFunctionExists.c.o -o cmTC_95326   && :
/usr/lib/gcc/x86_64-pc-linux-gnu/10.2.0/../../../../x86_64-pc-linux-gnu/bin/ld: CMakeFiles/cmTC_95326.dir/CheckFunctionExists.c.o: in function `main':
CheckFunctionExists.c:(.text.startup+0xc): undefined reference to `sin'
collect2: error: ld returned 1 exit status
ninja: build stopped: subcommand failed.



Performing C++ SOURCE FILE Test MGL_HAVE_C99_COMPLEX failed with the following output:
Change Dir: /var/tmp/portage/sci-libs/mathgl-2.4.4/work/mathgl-2.4.4_build/CMakeFiles/CMakeTmp

Run Build Command(s):/usr/bin/ninja cmTC_b21fd && [1/2] Building CXX object CMakeFiles/cmTC_b21fd.dir/src.cxx.o
FAILED: CMakeFiles/cmTC_b21fd.dir/src.cxx.o 
/usr/bin/x86_64-pc-linux-gnu-g++ -DMGL_HAVE_C99_COMPLEX   -DNDEBUG -O2 -pipe -march=native -fno-diagnostics-color -o CMakeFiles/cmTC_b21fd.dir/src.cxx.o -c src.cxx
src.cxx: In function ‘int main(int, char**)’:
src.cxx:5:20: error: unable to find numeric literal operator ‘operator""i’
    5 |  double _Complex i=1.0i;
      |                    ^~~~
src.cxx:5:20: note: add ‘using namespace std::complex_literals’ (from ‘<complex>’) to enable the C++14 user-defined literal suffixes
src.cxx:5:20: note: or use ‘j’ instead of ‘i’ for the GNU built-in suffix
ninja: build stopped: subcommand failed.


Source file was:
#include <complex>
	#include <complex.h>
	int main(int argc, char *args[])
	{std::complex<double> c(2.0, 1.0);
	double _Complex i=1.0i;
	double _Complex *a = reinterpret_cast<double _Complex *>(&c);
	std::complex<double> b(*a);return 0;}