use macro for /usr/local/plan9
diff --git a/man/man3/dial.3 b/man/man3/dial.3
index 5110227..36364f3 100644
--- a/man/man3/dial.3
+++ b/man/man3/dial.3
@@ -299,11 +299,11 @@
 }
 .EE
 .SH SOURCE
-.B /usr/local/plan9/src/lib9/dial.c
+.B \*9/src/lib9/dial.c
 .br
-.B /usr/local/plan9/src/lib9/announce.c
+.B \*9/src/lib9/announce.c
 .br
-.B /usr/local/plan9/src/lib9/_p9dialparse.c
+.B \*9/src/lib9/_p9dialparse.c
 .SH DIAGNOSTICS
 .IR Dial ,
 .IR announce ,