added unused sys functions to avoid warning on compile

tests/C/test_malloc/test_malloc.c

@@ -2,10 +2,14 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <stdbool.h>
+#include <errno.h>
+#include <sys/stat.h>
 
 #define BUFFER_SIZE (512)
 #define TRACE (*(unsigned char *)0x40000000)
 
+extern int  errno;
+
 int _write(int file, const char *ptr, int len) {
   int x;
 
@@ -16,16 +20,46 @@ int _write(int file, const char *ptr, int len) {
   return (len);
 }
 
+int _read (int   file, char *ptr, int   len) {
+  return  0;
+}  
+
+int _close (int   file) {
+  errno = EBADF;
+  return -1;
+} 
+
+int _fstat (int file, struct stat *st) {
+  st->st_mode = S_IFCHR;
+  return  0;
+}   
+
+int _isatty (int   file) {
+  return  1;
+} 
+
+int _lseek (int file, int offset, int whence) {
+  return  0;
+} 
 
 int main(void) {
   uint16_t *buffA, *buffB;  
   bool test_ok = true;
+  uint8_t *buffC;
   
   printf("Malloc Test\n");
 
+  printf("buffA: %p\n", (void *) buffA);
+  printf("buffB: %p\n", (void *) buffB);
+  printf("buffC: %p\n", (void *) buffC);
+  
   buffA = malloc(BUFFER_SIZE * sizeof(uint16_t));
   buffB = malloc(BUFFER_SIZE * sizeof(uint16_t));
 
+  printf("buffA: %p\n", (void *) buffA);
+  printf("buffB: %p\n", (void *) buffB);
+  printf("buffC: %p\n", (void *) buffC);
+  
   if ( (buffA == NULL ) || (buffB == NULL) ) {
 	  printf("Error malloc\n");
   }
@@ -34,7 +68,6 @@ int main(void) {
      buffA[i] = i;
   }
  
- 
   memcpy(buffB, buffA, BUFFER_SIZE * sizeof(uint16_t));
 
   for(int i=0;i<BUFFER_SIZE;i++) {
@@ -45,6 +78,17 @@ int main(void) {
     }
   }
   
+  free(buffA);
+  free(buffB);
+
+  printf("buffA: %p\n", (void *) buffA);
+  printf("buffB: %p\n", (void *) buffB);
+  printf("buffC: %p\n", (void *) buffC);
+ 
+  /* buffC should reuse address previously used by buffA (?) */
+  buffC = malloc(512);
+  printf("buffC: %p\n", (void *) buffC);
+  
   if (test_ok == true) {
     printf("Test were OK\n");
   }