cc -pthread  -Wall -Wextra -Werror=implicit-function-declaration signal/psiginfo.c -o signal/psiginfo -D_GNU_SOURCE -D_BSD_SOURCE -D_ALL_SOURCE -D_DEFAULT_SOURCE  -lm -lpthread  -liconv
signal/psiginfo.c:20:2: error: call to undeclared function 'psiginfo'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
   20 |         psiginfo(&info, "foo");
      |         ^
1 error generated.