expose sched.h functions (closes #12655)
diff --git a/configure.in b/configure.in
index 95ceab8..86e1a98 100644
--- a/configure.in
+++ b/configure.in
@@ -1301,7 +1301,7 @@
AC_CHECK_HEADERS(asm/types.h conio.h curses.h direct.h dlfcn.h errno.h \
fcntl.h grp.h \
ieeefp.h io.h langinfo.h libintl.h ncurses.h poll.h process.h pthread.h \
-shadow.h signal.h stdint.h stropts.h termios.h \
+sched.h shadow.h signal.h stdint.h stropts.h termios.h \
unistd.h utime.h \
sys/audioio.h sys/bsdtty.h sys/epoll.h sys/event.h sys/file.h sys/loadavg.h \
sys/lock.h sys/mkdev.h sys/modem.h \