cc -O2 -pipe -pthread -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations complex/ccoshl.c -o complex/ccoshl -D_POSIX_C_SOURCE=202405L -lm -lpthread -lrt -lstdthreads -lcrypt complex/ccoshl.c:5:51: error: call to undeclared library function 'ccoshl' with type '_Complex long double (_Complex long double)'; ISO C99 and later do not support implicit function declarations [-Werror,-Wimplicit-function-declaration] 5 | long double complex (*foo)(long double complex) = ccoshl; | ^ complex/ccoshl.c:5:51: note: include the header or explicitly provide a declaration for 'ccoshl' 1 error generated.