cc -pthread  -Wall -Wextra -Werror=implicit-function-declaration unistd/nice.c -o unistd/nice -D_GNU_SOURCE -D_BSD_SOURCE -D_ALL_SOURCE -D_DEFAULT_SOURCE -lm -lpthread -lrt -lintl -liconv
unistd/nice.c: In function ‘main’:
unistd/nice.c:11:14: error: implicit declaration of function ‘nice’ [-Wimplicit-function-declaration]
   11 |         if ( nice(0) < 0 && errno )
      |              ^~~~