newlib/doc/makedoc.c: if realloc() fails, exit with an error message.

newlib/doc/makedoc.c

@@ -135,6 +135,11 @@ catchar (string_type *buffer, char ch)
   {
     buffer->size *=2;
     buffer->ptr = realloc(buffer->ptr, buffer->size);
+    if (!buffer->ptr)
+    {
+      fprintf(stderr,"Can't allocate memory\n");
+      exit(1);
+    }
   }
 
   buffer->ptr[buffer->write_idx ++ ] = ch;