cc -pthread  -Wall -Wextra newlocale.c -o newlocale -D_GNU_SOURCE -D_BSD_SOURCE -D_ALL_SOURCE -D_DEFAULT_SOURCE  -lm -lpthread  -liconv
newlocale.c:9:2: error: use of undeclared identifier 'locale_t'
        locale_t locale = newlocale(LC_ALL_MASK, "C", (locale_t) 0);
        ^
newlocale.c:10:18: error: use of undeclared identifier 'locale_t'
        if ( locale == (locale_t) 0 )
                        ^
newlocale.c:10:7: error: use of undeclared identifier 'locale'
        if ( locale == (locale_t) 0 )
             ^
3 errors generated.