diff --git a/INSTALL b/INSTALL
index 099ab2bb..09c61e47 100644
--- a/INSTALL
+++ b/INSTALL
@@ -13,3 +13,18 @@ As of 2.4.7, rsync uses Eric Troan's popt option-parsing library.  A
 cut-down copy of release 1.5 is included in the rsync distribution,
 and will be used it there is no popt library on your build host, or if
 the --with-included-popt option is passed to ./configure.
+
+
+
+HP-UX NOTES
+-----------
+
+The HP-UX 10.10 "bundled" C compiler seems not to be able to cope with
+ANSI C.  You may see this error message in config.log if ./configure
+fails:
+
+  (Bundled) cc: "configure", line 2162: error 1705: Function prototypes are an ANSI feature.
+
+Install gcc or HP's "ANSI/C Compiler".
+
+