use macro for /usr/local/plan9
diff --git a/man/man3/cachechars.3 b/man/man3/cachechars.3
index bb7a475..b0c7abf 100644
--- a/man/man3/cachechars.3
+++ b/man/man3/cachechars.3
@@ -300,7 +300,7 @@
 Thus, characters or subfonts with small ages are the best candidates
 for replacement when the cache is full.
 .SH SOURCE
-.B /usr/local/plan9/src/libdraw
+.B \*9/src/libdraw
 .SH SEE ALSO
 .IR graphics (3),
 .IR allocimage (3),