Implicit declaration of a function "exit"

[TovStalin]

When I hitting "Make", the error is occured:

src/dmitry.c: In function «main»:
src/dmitry.c:37:17: error: implicit declaration of function «exit» [-Wimplicit-function-declaration]
   37 |                 exit(1);
      |                 ^~~~
src/dmitry.c:16:1: remark: include «<stdlib.h>» or provide a declaration of «exit»
   15 | #include <arpa/inet.h>
  +++ |+#include <stdlib.h>
   16 | 
src/dmitry.c:37:17: warning: incompatible implicit declaration of an internal function «exit» [-Wbuiltin-declaration-mismatch]
   37 |                 exit(1);
      |                 ^~~~
src/dmitry.c:37:17: remark: include «<stdlib.h>» or provide a declaration for «exit»
src/dmitry.c:67:41: warning: incompatible implicit declaration of an internal function «exit» [-Wbuiltin-declaration-mismatch]
   67 |                                         exit(0);
      |                                         ^~~~
src/dmitry.c:67:41: remark: include «<stdlib.h>» or provide a declaration for «exit»
src/dmitry.c:104:33: warning: incompatible implicit declaration of an internal function «exit» [-Wbuiltin-declaration-mismatch]
  104 |                                 exit(1);
      |                                 ^~~~
src/dmitry.c:104:33: remark: include «<stdlib.h>» or provide a declaration for «exit»