These are disabled by the configure code, so this is just fixing an
inconsistency in the MSVC code.
Backpatch to all live branches.
my $basetarg = basename($output);
my $headerflag = ($make =~ /^$basetarg:\s+BISONFLAGS\b.*-d/m ? '-d' : '');
-system("bison $headerflag $input -o $output");
+my $nodep = $bisonver ge '3.0' ? "-Wno-deprecated" : "";
+
+system("bison $nodep $headerflag $input -o $output");
exit $? >> 8;