fortran: don't complain about script args if we're not building fortran

refs trac:4917

This commit was SVN r32766.

The following Trac tickets were found above:
  Ticket 4917 --> https://svn.open-mpi.org/trac/ompi/ticket/4917

ompi/mpi/fortran/base/gen-mpi-sizeof.pl

@@ -46,11 +46,14 @@ my $ok = Getopt::Long::GetOptions("header=s" => \$header_arg,
 die "Must specify header and/or impl filenames to output"
     if (!defined($header_arg) && !defined($impl_arg));
 die "ierror handling must be optional or mandatory"
-    if (lc($ierror_arg) ne "optional" && lc($ierror_arg) ne "mandatory");
+    if (defined($generate_arg) && $generate_arg &&
+        (lc($ierror_arg) ne "optional" && lc($ierror_arg) ne "mandatory"));
 die "max array rank must be >= 4 and <=15"
-    if (!defined($maxrank_arg) || $maxrank_arg < 4 || $maxrank_arg > 15);
+    if (defined($generate_arg) && $generate_arg &&
+        (!defined($maxrank_arg) || $maxrank_arg < 4 || $maxrank_arg > 15));
 die "Must specify --pmpi and/or --mpi if --impl is specified"
-    if (defined($impl_arg) && !defined($mpi_arg) && !defined($pmpi_arg));
+    if (defined($generate_arg) && $generate_arg &&
+        (defined($impl_arg) && !defined($mpi_arg) && !defined($pmpi_arg)));
 
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