_configtest.c:1:5: warning: conflicting types for built-in function ‘cabs’; expected ‘double(_Complex double)’ [-Wbuiltin-declaration-mismatch]
    1 | int cabs (void);
      |     ^~~~
_configtest.c:1:1: note: ‘cabs’ is declared in header ‘<complex.h>’
  +++ |+#include <complex.h>
    1 | int cabs (void);
_configtest.c:2:5: warning: conflicting types for built-in function ‘cacos’; expected ‘_Complex double(_Complex double)’ [-Wbuiltin-declaration-mismatch]
    2 | int cacos (void);
      |     ^~~~~
_configtest.c:2:5: note: ‘cacos’ is declared in header ‘<complex.h>’
_configtest.c:3:5: warning: conflicting types for built-in function ‘cacosh’; expected ‘_Complex double(_Complex double)’ [-Wbuiltin-declaration-mismatch]
    3 | int cacosh (void);
      |     ^~~~~~
_configtest.c:3:5: note: ‘cacosh’ is declared in header ‘<complex.h>’
_configtest.c:4:5: warning: conflicting types for built-in function ‘carg’; expected ‘double(_Complex double)’ [-Wbuiltin-declaration-mismatch]
    4 | int carg (void);
      |     ^~~~
_configtest.c:4:5: note: ‘carg’ is declared in header ‘<complex.h>’
_configtest.c:5:5: warning: conflicting types for built-in function ‘casin’; expected ‘_Complex double(_Complex double)’ [-Wbuiltin-declaration-mismatch]
    5 | int casin (void);
      |     ^~~~~
_configtest.c:5:5: note: ‘casin’ is declared in header ‘<complex.h>’
_configtest.c:6:5: warning: conflicting types for built-in function ‘casinh’; expected ‘_Complex double(_Complex double)’ [-Wbuiltin-declaration-mismatch]
    6 | int casinh (void);
      |     ^~~~~~
_configtest.c:6:5: note: ‘casinh’ is declared in header ‘<complex.h>’
_configtest.c:7:5: warning: conflicting types for built-in function ‘catan’; expected ‘_Complex double(_Complex double)’ [-Wbuiltin-declaration-mismatch]
    7 | int catan (void);
      |     ^~~~~
_configtest.c:7:5: note: ‘catan’ is declared in header ‘<complex.h>’
_configtest.c:8:5: warning: conflicting types for built-in function ‘catanh’; expected ‘_Complex double(_Complex double)’ [-Wbuiltin-declaration-mismatch]
    8 | int catanh (void);
      |     ^~~~~~
_configtest.c:8:5: note: ‘catanh’ is declared in header ‘<complex.h>’
_configtest.c:9:5: warning: conflicting types for built-in function ‘ccos’; expected ‘_Complex double(_Complex double)’ [-Wbuiltin-declaration-mismatch]
    9 | int ccos (void);
      |     ^~~~
_configtest.c:9:5: note: ‘ccos’ is declared in header ‘<complex.h>’
_configtest.c:10:5: warning: conflicting types for built-in function ‘ccosh’; expected ‘_Complex double(_Complex double)’ [-Wbuiltin-declaration-mismatch]
   10 | int ccosh (void);
      |     ^~~~~
_configtest.c:10:5: note: ‘ccosh’ is declared in header ‘<complex.h>’
_configtest.c:11:5: warning: conflicting types for built-in function ‘cexp’; expected ‘_Complex double(_Complex double)’ [-Wbuiltin-declaration-mismatch]
   11 | int cexp (void);
      |     ^~~~
_configtest.c:11:5: note: ‘cexp’ is declared in header ‘<complex.h>’
_configtest.c:12:5: warning: conflicting types for built-in function ‘cimag’; expected ‘double(_Complex double)’ [-Wbuiltin-declaration-mismatch]
   12 | int cimag (void);
      |     ^~~~~
_configtest.c:12:5: note: ‘cimag’ is declared in header ‘<complex.h>’
_configtest.c:13:5: warning: conflicting types for built-in function ‘clog’; expected ‘_Complex double(_Complex double)’ [-Wbuiltin-declaration-mismatch]
   13 | int clog (void);
      |     ^~~~
_configtest.c:13:5: note: ‘clog’ is declared in header ‘<complex.h>’
_configtest.c:14:5: warning: conflicting types for built-in function ‘conj’; expected ‘_Complex double(_Complex double)’ [-Wbuiltin-declaration-mismatch]
   14 | int conj (void);
      |     ^~~~
_configtest.c:14:5: note: ‘conj’ is declared in header ‘<complex.h>’
_configtest.c:15:5: warning: conflicting types for built-in function ‘cpow’; expected ‘_Complex double(_Complex double,  _Complex double)’ [-Wbuiltin-declaration-mismatch]
   15 | int cpow (void);
      |     ^~~~
_configtest.c:15:5: note: ‘cpow’ is declared in header ‘<complex.h>’
_configtest.c:16:5: warning: conflicting types for built-in function ‘cproj’; expected ‘_Complex double(_Complex double)’ [-Wbuiltin-declaration-mismatch]
   16 | int cproj (void);
      |     ^~~~~
_configtest.c:16:5: note: ‘cproj’ is declared in header ‘<complex.h>’
_configtest.c:17:5: warning: conflicting types for built-in function ‘creal’; expected ‘double(_Complex double)’ [-Wbuiltin-declaration-mismatch]
   17 | int creal (void);
      |     ^~~~~
_configtest.c:17:5: note: ‘creal’ is declared in header ‘<complex.h>’
_configtest.c:18:5: warning: conflicting types for built-in function ‘csin’; expected ‘_Complex double(_Complex double)’ [-Wbuiltin-declaration-mismatch]
   18 | int csin (void);
      |     ^~~~
_configtest.c:18:5: note: ‘csin’ is declared in header ‘<complex.h>’
_configtest.c:19:5: warning: conflicting types for built-in function ‘csinh’; expected ‘_Complex double(_Complex double)’ [-Wbuiltin-declaration-mismatch]
   19 | int csinh (void);
      |     ^~~~~
_configtest.c:19:5: note: ‘csinh’ is declared in header ‘<complex.h>’
_configtest.c:20:5: warning: conflicting types for built-in function ‘csqrt’; expected ‘_Complex double(_Complex double)’ [-Wbuiltin-declaration-mismatch]
   20 | int csqrt (void);
      |     ^~~~~
_configtest.c:20:5: note: ‘csqrt’ is declared in header ‘<complex.h>’
_configtest.c:21:5: warning: conflicting types for built-in function ‘ctan’; expected ‘_Complex double(_Complex double)’ [-Wbuiltin-declaration-mismatch]
   21 | int ctan (void);
      |     ^~~~
_configtest.c:21:5: note: ‘ctan’ is declared in header ‘<complex.h>’
_configtest.c:22:5: warning: conflicting types for built-in function ‘ctanh’; expected ‘_Complex double(_Complex double)’ [-Wbuiltin-declaration-mismatch]
   22 | int ctanh (void);
      |     ^~~~~
_configtest.c:22:5: note: ‘ctanh’ is declared in header ‘<complex.h>’