cc -pthread  -Wall -Wextra getlocalename_l.c -o getlocalename_l -D_GNU_SOURCE -D_BSD_SOURCE -D_ALL_SOURCE -D_DEFAULT_SOURCE  -lm -lpthread  -liconv
getlocalename_l.c:9:21: error: implicit declaration of function 'getlocalename_l' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
        const char* name = getlocalename_l(LC_COLLATE, LC_GLOBAL_LOCALE);
                           ^
getlocalename_l.c:9:49: error: use of undeclared identifier 'LC_GLOBAL_LOCALE'
        const char* name = getlocalename_l(LC_COLLATE, LC_GLOBAL_LOCALE);
                                                       ^
getlocalename_l.c:14:2: error: use of undeclared identifier 'locale_t'
        locale_t locale = newlocale(LC_COLLATE_MASK, "C", (locale_t) 0);
        ^
getlocalename_l.c:15:18: error: use of undeclared identifier 'locale_t'
        if ( locale == (locale_t) 0 )
                        ^
getlocalename_l.c:15:7: error: use of undeclared identifier 'locale'
        if ( locale == (locale_t) 0 )
             ^
getlocalename_l.c:17:37: error: use of undeclared identifier 'locale'
        name = getlocalename_l(LC_COLLATE, locale);
                                           ^
6 errors generated.