Fix Ubuntu 16.04 build

Was broken by #681.

configure

@@ -4756,6 +4756,16 @@ else
 fi
 
 
+ac_fn_cxx_check_member "$LINENO" "struct statx" "ino" "ac_cv_member_struct_statx_ino" "$ac_includes_default"
+if test "x$ac_cv_member_struct_statx_ino" = xyes; then :
+
+cat >>confdefs.h <<_ACEOF
+#define HAVE_STATX 1
+_ACEOF
+
+fi
+
+
 ac_fn_cxx_check_member "$LINENO" "struct statx" "stx_mnt_id" "ac_cv_member_struct_statx_stx_mnt_id" "$ac_includes_default"
 if test "x$ac_cv_member_struct_statx_stx_mnt_id" = xyes; then :
 
@@ -4769,6 +4779,7 @@ fi
 
 
 
+
     # Determine if this is a required or an optional subproject
 
 

fesvr/fesvr.ac

@@ -1,5 +1,10 @@
 AC_CHECK_LIB(pthread, pthread_create, [], [AC_MSG_ERROR([libpthread is required])])
 
+AC_CHECK_MEMBER(struct statx.ino,
+  AC_DEFINE_UNQUOTED(HAVE_STATX, 1, [Define to 1 if struct statx exists.]),
+  ,
+)
+
 AC_CHECK_MEMBER(struct statx.stx_mnt_id,
   AC_DEFINE_UNQUOTED(HAVE_STATX_MNT_ID, 1, [Define to 1 if struct statx has stx_mnt_id.]),
   ,

fesvr/syscall.cc

@@ -64,6 +64,7 @@ struct riscv_statx_timestamp {
     target_endian<int32_t>  __reserved;
 };
 
+#ifdef HAVE_STATX
 struct riscv_statx
 {
     target_endian<uint32_t> mask;
@@ -134,6 +135,7 @@ struct riscv_statx
 #endif      
       {}
 };
+#endif
 
 syscall_t::syscall_t(htif_t* htif)
   : htif(htif), memif(&htif->memif()), table(2048)
@@ -303,6 +305,9 @@ reg_t syscall_t::sys_lstat(reg_t pname, reg_t len, reg_t pbuf, reg_t a3, reg_t a
 
 reg_t syscall_t::sys_statx(reg_t fd, reg_t pname, reg_t len, reg_t flags, reg_t mask, reg_t pbuf, reg_t a6)
 {
+#ifndef HAVE_STATX
+  return -ENOSYS;
+#else
   std::vector<char> name(len);
   memif->read(pname, len, &name[0]);
 
@@ -314,6 +319,7 @@ reg_t syscall_t::sys_statx(reg_t fd, reg_t pname, reg_t len, reg_t flags, reg_t
     memif->write(pbuf, sizeof(rbuf), &rbuf);
   }
   return ret;
+#endif
 }
 
 #define AT_SYSCALL(syscall, fd, name, ...) \