use macro for /usr/local/plan9
diff --git a/man/man1/seq.1 b/man/man1/seq.1
index 5fda241..3f295c0 100644
--- a/man/man1/seq.1
+++ b/man/man1/seq.1
@@ -64,7 +64,7 @@
 Print
 .BR "0.00 0.05 0.10" .
 .SH SOURCE
-.B /usr/local/plan9/src/cmd/seq.c
+.B \*9/src/cmd/seq.c
 .SH BUGS
 Option
 .B -w