cc -O2 -pthread  -Wall -Wextra -Werror=implicit-function-declaration stdlib/qsort_r.c -o stdlib/qsort_r -D_GNU_SOURCE -D_BSD_SOURCE -D_ALL_SOURCE -D_DEFAULT_SOURCE  -lm -lpthread -lrt  -lintl -lcrypt
stdlib/qsort_r.c: In function 'main':
stdlib/qsort_r.c:21:2: error: implicit declaration of function 'qsort_r'; did you mean 'qsort'? [-Werror=implicit-function-declaration]
   21 |  qsort_r(numbers, sizeof(numbers) / sizeof(int), sizeof(int), compare_int_r,
      |  ^~~~~~~
      |  qsort
cc1: some warnings being treated as errors