Create a config.h file. Check for <sched.h>.

From-SVN: r35696
diff --git a/libobjc/configure.in b/libobjc/configure.in
index 3fb507d..9183e52 100644
--- a/libobjc/configure.in
+++ b/libobjc/configure.in
@@ -21,7 +21,7 @@
 
 AC_PREREQ(2.13)
 AC_INIT(objc/objc.h)
-#AC_CONFIG_HEADER(config.h)
+AC_CONFIG_HEADER(config.h)
 
 if test "${srcdir}" = "." ; then
   if test "${with_target_subdir}" != "." ; then
@@ -91,6 +91,8 @@
 
 AC_HEADER_STDC
 
+AC_CHECK_HEADERS(sched.h)
+
 # Determine CFLAGS for gthread.
 
 AC_CACHE_CHECK([for gthread cflags],objc_cv_gthread_flags,