fix: less libs

replaced stdio's printf() + fflush() with with unistd's single write()
sadly it did not reduce size of a binary

main.c

@@ -1,11 +1,9 @@
-#include <stdio.h>
 #include <unistd.h>
 
 int main() {
   while (1) {
     sleep(20);
-    printf("*");
-    fflush(NULL);
+    write(1, "*", 1);
   }
   return 0;
 }