--- a/configure.in	Mon May 14 04:16:19 2001 +0000
+++ b/configure.in	Mon May 14 04:52:49 2001 +0000
@@ -2757,7 +2757,7 @@
     cd ..
     rm -fr conftestdir
     for word in $xmkmf_defines; do
-      case "$word" in 
+      case "$word" in
       -D__STDC__*) ;;
       -D* )
 	sym=`echo '' $word | sed -e 's:^ *-D::' -e 's:=.*::'`
@@ -2825,7 +2825,7 @@
 #include <X11/Xlib.h>
 extern Bool XRegisterIMInstantiateCallback(
    Display*, struct _XrmHashBucketRec*, char*, char*, XIMProc, XPointer*);
-], [], 
+], [],
   [AC_MSG_RESULT(yes)],
   [AC_MSG_RESULT(no)
    AC_DEFINE(XREGISTERIMINSTANTIATECALLBACK_NONSTANDARD_PROTOTYPE)])
@@ -3710,7 +3710,7 @@
 AC_CHECK_FUNCS(cbrt closedir dup2 eaccess fmod fpathconf frexp ftime getaddrinfo gethostname getnameinfo getpagesize gettimeofday getcwd getwd logb lrand48 matherr mkdir mktime perror poll random rename res_init rint rmdir select setitimer setpgid setlocale setsid sigblock sighold sigprocmask snprintf stpcpy strerror tzset ulimit usleep waitpid vsnprintf fsync ftruncate umask)
 
 dnl ----------------------------------------------------------------
-dnl Check for PTY support functions.
+dnl Check for Unixoid pty/process support.
 dnl ----------------------------------------------------------------
 
 dnl There is no "standard" pty allocation method.  Every system is different.
@@ -3728,10 +3728,20 @@
   AC_CHECK_LIB(util, openpty, have_openpty=yes need_libutil=yes)])
 if test "$have_openpty" = "yes"; then
   AC_DEFINE(HAVE_OPENPTY)
-  AC_CHECK_HEADERS(pty.h libutil.h util.h, break)
+  AC_CHECK_HEADERS(libutil.h util.h, break)
   test "$need_libutil" = "yes" && XE_APPEND(-lutil, libs_system)
 fi
 
+dnl Check for system-specific pty header files
+dnl Often the TIOCSIG* symbols are hiding there.
+case "$opsys" in
+  dnl HPUX pty.h #defines TRUE and FALSE, so just use ptyio.h there.
+  hpux*) AC_CHECK_HEADERS(sys/ptyio.h) ;;
+  *) AC_CHECK_HEADERS(pty.h)
+     test "$ac_cv_header_pty_h" = "no" && AC_CHECK_HEADERS(sys/pty.h)
+     ;;
+esac
+
 dnl Check for STREAM support functions.
 dnl Confusingly, "str" means both "string" and "SysV Streams".
 AC_CHECK_HEADERS(stropts.h)
@@ -3917,7 +3927,7 @@
 test "$have_mmap" = "yes" && AC_DEFINE(HAVE_MMAP)
 
 dnl By default we switch off rel-alloc on cygwin as it generally causes us grief
-case "$opsys" in cygwin*) 
+case "$opsys" in cygwin*)
 	test "$rel_alloc" = "default" && rel_alloc=no ;;
 esac
 dnl rel_alloc requires either GNU malloc or system malloc with mmap