cc -O2 -pipe  -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 
signal/psiginfo.c:20:2: error: call to undeclared function 'psiginfo'; ISO C99 and later do not support implicit function declarations [-Werror,-Wimplicit-function-declaration]
        psiginfo(&info, "foo");
        ^
1 error generated.