further semihosting support

libwrap/semihosting/semihosting.h

@@ -1,8 +1,11 @@
 #ifndef SEMIHOSTING_H
 #define SEMIHOSTING_H
 
+#include <unistd.h>
+#include <sys/types.h>
 //int32_t trace_write(const char* buf, uint32_t nbyte);
 
+void sh_seek(int, off_t);
 void sh_write0(const char* buf);
 void sh_writec(char c);
 char sh_readc(void);