diff --git a/src/configure.in b/src/configure.in
index ea07cae30132d538c95d2f8db01a982a702eb13f..10b97c8b3c5ebbf20029c3e53a1b9384cb98b261 100644
--- a/src/configure.in
+++ b/src/configure.in
@@ -1,4 +1,4 @@
-AC_REVISION("$Id: configure.in,v 1.228 1998/08/09 12:46:03 grubba Exp $")
+AC_REVISION("$Id: configure.in,v 1.229 1998/08/09 14:43:06 grubba Exp $")
 AC_INIT(interpret.c)
 AC_CONFIG_HEADER(machine.h)
 
@@ -325,10 +325,14 @@ if test $cflags_is_set = no; then
 
   # HP-UX
   AC_SYS_OS_COMPILER_FLAG(HP-UX,-D__STDC_EXT__,stdc_ext,CFLAGS)
+  AC_SYS_OS_COMPILER_FLAG(HP-UX,+ESlit,plus_ESlit,OPTIMIZE)
   AC_SYS_OS_COMPILER_FLAG(HP-UX,+Odataprefetch,plus_Odataprefetch,OPTIMIZE)
   AC_SYS_OS_COMPILER_FLAG(HP-UX,+Ofailsafe,plus_Ofailsafe,OPTIMIZE)
   AC_SYS_OS_COMPILER_FLAG(HP-UX,+O3,plus_O3,OPTIMIZE)
-  # Ignore warnings 530 and 414 if you turn this on.
+  # Ignore the following warnings if you enable +w1
+  #   414 Optimization reduced to +O2 for compatibility with Debug.
+  #   530 Casting from loose to strict alignment
+  #   558 Empty declaration.
   # AC_SYS_OS_COMPILER_FLAG(HP-UX,+w1,plus_w1,WARN)
 
   # OSF/1