diff --git a/src/configure.in b/src/configure.in
index 0cfdf45fd3483176ecf0397da03b5fbcc4e4e019..9717446598a7d019408d9f1693ec4c90673e3a3e 100644
--- a/src/configure.in
+++ b/src/configure.in
@@ -1,4 +1,4 @@
-AC_REVISION("$Id: configure.in,v 1.208 1998/06/28 16:02:45 grubba Exp $")
+AC_REVISION("$Id: configure.in,v 1.209 1998/07/01 20:21:07 grubba Exp $")
 AC_INIT(interpret.c)
 AC_CONFIG_HEADER(machine.h)
 
@@ -283,6 +283,7 @@ if test $cflags_is_set = no; then
   # AC_SYS_OS_COMPILER_FLAG(Solaris,-Xc,Xc,WARN)
 
   # HP-UX
+  AC_SYS_OS_COMPILER_FLAG(HP-UX,-D__STDC_EXT__,stdc_ext,CFLAGS)
   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)