/opt/IBM/openxlC/17.1.1/bin/ibm-clang -pthread -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations string/strlcat.c -o string/strlcat -D_POSIX_C_SOURCE=202405L -lm -lpthread -lrt -latomic string/strlcat.c:5:63: error: call to undeclared library function 'strlcat' with type 'unsigned long (char *, const char *, unsigned long)'; ISO C99 and later do not support implicit function declarations [-Werror,-Wimplicit-function-declaration] size_t (*foo)(char *restrict, const char *restrict, size_t) = strlcat; ^ string/strlcat.c:5:63: note: include the header or explicitly provide a declaration for 'strlcat' 1 error generated.