cc -pthread  -Wall -Wextra -Werror=implicit-function-declaration langinfo/nl_langinfo_l.c -o langinfo/nl_langinfo_l -D_GNU_SOURCE -D_BSD_SOURCE -D_ALL_SOURCE -D_DEFAULT_SOURCE  -lm -lpthread  -liconv
langinfo/nl_langinfo_l.c:13:17: error: call to undeclared function 'nl_langinfo_l'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
   13 |         char* output = nl_langinfo_l(MON_1, locale);
      |                        ^
langinfo/nl_langinfo_l.c:13:17: note: did you mean 'nl_langinfo'?
/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include/_langinfo.h:116:20: note: 'nl_langinfo' declared here
  116 | char    *_LIBC_CSTR   nl_langinfo(nl_item);
      |                       ^
langinfo/nl_langinfo_l.c:13:8: error: incompatible integer to pointer conversion initializing 'char *' with an expression of type 'int' [-Wint-conversion]
   13 |         char* output = nl_langinfo_l(MON_1, locale);
      |               ^        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
2 errors generated.