hurd: Fix build

GNU/Hurd does not impose an IOV_MAX limitation.

We'd however rather avoid allocating without any bound and batch with a
reasonable size.

Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>

Author: sthibaul

ompi/mca/fbtl/posix/fbtl_posix_preadv.c

@@ -33,6 +33,9 @@
 #include "ompi/constants.h"
 #include "ompi/mca/fbtl/fbtl.h"
 
+#ifndef IOV_MAX
+#define IOV_MAX 1024
+#endif
 
 static ssize_t mca_fbtl_posix_preadv_datasieving (ompio_file_t *fh, struct flock *lock, int *lock_counter);
 static ssize_t mca_fbtl_posix_preadv_generic (ompio_file_t *fh, struct flock *lock, int *lock_counter);

ompi/mca/fbtl/posix/fbtl_posix_pwritev.c

@@ -33,6 +33,10 @@
 #include "ompi/constants.h"
 #include "ompi/mca/fbtl/fbtl.h"
 
+#ifndef IOV_MAX
+#define IOV_MAX 1024
+#endif
+
 static ssize_t mca_fbtl_posix_pwritev_datasieving (ompio_file_t *fh, struct flock *lock, int *lock_counter );
 static ssize_t mca_fbtl_posix_pwritev_generic (ompio_file_t *fh, struct flock *lock, int *lock_counter );
 static ssize_t mca_fbtl_posix_pwritev_single (ompio_file_t *fh, struct flock *lock, int *lock_counter );