cc -pthread -Wall -Wextra -Werror=implicit-function-declaration wctype/iswprint_l.c -o wctype/iswprint_l -D_GNU_SOURCE -D_BSD_SOURCE -D_ALL_SOURCE -D_DEFAULT_SOURCE -lm -lpthread -liconv wctype/iswprint_l.c:15:8: error: call to undeclared function 'iswprint_l'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration] 15 | if ( !iswprint_l(wc1, locale) ) | ^ wctype/iswprint_l.c:15:8: note: did you mean 'iswprint'? /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include/___wctype.h:126:1: note: 'iswprint' declared here 126 | iswprint(wint_t _wc) | ^ 1 error generated.