Fix stripping program name from error messages on Windows.
diff --git a/regress/NiHTest.pm b/regress/NiHTest.pm
index 736ebae..4e3cc4c 100644
--- a/regress/NiHTest.pm
+++ b/regress/NiHTest.pm
@@ -1188,7 +1188,7 @@
 			chomp $line;
 		}
 
-		$line =~ s/^[^: ]*$prg: //;
+		$line =~ s/^[^: ]*$prg(\.exe)?: //;
 		if (defined($self->{test}->{'stderr-replace'})) {
 			$line = $self->stderr_rewrite($self->{test}->{'stderr-replace'}, $line);
 		}
@@ -1218,7 +1218,7 @@
 	foreach my $line (@$stderr_buf) {
 		$line =~ s/[\r\n]+$//;
 
-		$line =~ s/^[^: ]*$prg: //;
+		$line =~ s/^[^: ]*$prg(\.exe)?: //;
 		if (defined($self->{test}->{'stderr-replace'})) {
 			$line = $self->stderr_rewrite($self->{test}->{'stderr-replace'}, $line);
 		}