diff --git a/util/mkdef.pl b/util/mkdef.pl
index 0ad1a2d3e3d0ca7f43c645e22882b0c3605795ac..a2cc12619b2a7ba31fcf4270e97d12b06ad30a40 100755
--- a/util/mkdef.pl
+++ b/util/mkdef.pl
@@ -1572,7 +1572,7 @@ sub get_openssl_version()
 	while(<IN>) {
 		if (/OPENSSL_VERSION_TEXT\s+"OpenSSL (\d\.\d\.)(\d[a-z]*)(-| )/) {
 			my $suffix = $2;
-			my $baseversion = $1 =~ s/\./_/gr;
+			(my $baseversion = $1) =~ s/\./_/g;
 			close IN;
 			return ($baseversion."0", $baseversion.$suffix);
 		}