Move UNIX98_PTYS from src/s to configure

* configure.ac (UNIX98_PTYS): Move here from src/s.

* src/s/gnu-linux.h (UNIX98_PTYS): Let configure set it.

ChangeLog

@@ -8,7 +8,7 @@
 	(BROKEN_SIGPOLL, BROKEN_SIGPTY, FIRST_PTY_LETTER)
 	(G_SLICE_ALWAYS_MALLOC, PREFER_VSUSP, PTY_ITERATION, PTY_OPEN)
 	(PTY_NAME_SPRINTF, PTY_TTY_NAME_SPRINTF, RUN_TIME_REMAP)
-	(SETPGRP_RELEASES_CTTY, TAB3, TABDLY, RUN_TIME_REMAP)
+	(SETPGRP_RELEASES_CTTY, TAB3, TABDLY, RUN_TIME_REMAP, UNIX98_PTYS)
 	(XOS_NEEDS_TIME_H): Move here from src/s.
 
 2012-07-11  Glenn Morris  <rgm@gnu.org>

configure.ac

@@ -3340,6 +3340,7 @@ case $opsys in
   gnu-linux | gnu-kfreebsd )
     dnl if HAVE_GRANTPT
     if test "x$ac_cv_func_grantpt" = xyes; then
+      AC_DEFINE(UNIX98_PTYS, 1, [Define if the system has Unix98 PTYs.])
       AC_DEFINE(PTY_ITERATION, [int i; for (i = 0; i < 1; i++)] )
       dnl Note that grantpt and unlockpt may fork.  We must block SIGCHLD
       dnl to prevent sigchld_handler from intercepting the child's death.

src/ChangeLog

@@ -1,3 +1,7 @@
+2012-07-12  Glenn Morris  <rgm@gnu.org>
+
+	* s/gnu-linux.h (UNIX98_PTYS): Let configure set it.
+
 2012-07-12  Paul Eggert  <eggert@cs.ucla.edu>
 
 	Fix typos that broke OS X build.

src/s/gnu-linux.h

@@ -25,10 +25,6 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 #define USG
 #define GNU_LINUX
 
-#if defined HAVE_GRANTPT
-#define UNIX98_PTYS
-#endif  /* HAVE_GRANTPT */
-
 /* Here, on a separate page, add any special hacks needed
    to make Emacs work on this system.  For example,
    you might define certain system call names that don't