Many small edits.
diff --git a/man/man3/sleep.3 b/man/man3/sleep.3
index 7df6c33..0afa71d 100644
--- a/man/man3/sleep.3
+++ b/man/man3/sleep.3
@@ -43,3 +43,14 @@
 .SH DIAGNOSTICS
 These functions set
 .IR errstr .
+.SH BUGS
+To avoid name conflicts with the underlying system,
+.I sleep
+and
+.I alarm
+are preprocessor macros defined as
+.I p9sleep
+and
+.IR p9alarm ;
+see
+.IR intro (3).