diff --git a/src/tools/msvc/Mkvcbuild.pm b/src/tools/msvc/Mkvcbuild.pm
index ef315d88f9..5762c68c4e 100644
--- a/src/tools/msvc/Mkvcbuild.pm
+++ b/src/tools/msvc/Mkvcbuild.pm
@@ -131,7 +131,7 @@ sub mkvcbuild
 	our @pgcommonbkndfiles = @pgcommonallfiles;
 
 	our @pgfeutilsfiles = qw(
-	  mbprint.c print.c psqlscan.l psqlscan.c simple_list.c string_utils.c);
+	  conditional.c mbprint.c print.c psqlscan.l psqlscan.c simple_list.c string_utils.c);
 
 	$libpgport = $solution->AddProject('libpgport', 'lib', 'misc');
 	$libpgport->AddDefine('FRONTEND');