diff --git a/src/tools/msvc/Mkvcbuild.pm b/src/tools/msvc/Mkvcbuild.pm
index e0bf607..0f50fde 100644
--- a/src/tools/msvc/Mkvcbuild.pm
+++ b/src/tools/msvc/Mkvcbuild.pm
@@ -518,6 +518,15 @@ sub mkvcbuild
 		  $solution->AddProject('plperl', 'dll', 'PLs', 'src/pl/plperl');
 		$plperl->AddIncludeDir($solution->{options}->{perl} . '/lib/CORE');
 		$plperl->AddDefine('PLPERL_HAVE_UID_GID');
+
+		foreach my $f (split(" ",$Config{ccflags}))
+		{
+			if ($f =~ /^-D/)
+			{
+				$plperl->AddDefine($f);
+			}
+		}
+
 		foreach my $xs ('SPI.xs', 'Util.xs')
 		{
 			(my $xsc = $xs) =~ s/\.xs/.c/;