cc -pthread -Wall -Wextra -Werror=implicit-function-declaration ctype/ispunct_l.c -o ctype/ispunct_l -D_GNU_SOURCE -D_BSD_SOURCE -D_ALL_SOURCE -D_DEFAULT_SOURCE -lm -lpthread -liconv ctype/ispunct_l.c:15:8: error: call to undeclared function 'ispunct_l'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration] 15 | if ( !ispunct_l(c1, locale) ) | ^ ctype/ispunct_l.c:15:8: note: did you mean 'ispunct'? /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include/_ctype.h:266:1: note: 'ispunct' declared here 266 | ispunct(int _c) | ^ 1 error generated.