Add terminal width detection to llvm::sys::Process. This is needed to
fix Clang PRs 4148 and 4183.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@71448 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/autoconf/configure.ac b/autoconf/configure.ac
index 3c2cd36..cebdc80 100644
--- a/autoconf/configure.ac
+++ b/autoconf/configure.ac
@@ -826,7 +826,7 @@
 AC_CHECK_HEADERS([malloc.h setjmp.h signal.h stdint.h unistd.h utime.h])
 AC_CHECK_HEADERS([windows.h])
 AC_CHECK_HEADERS([sys/mman.h sys/param.h sys/resource.h sys/time.h])
-AC_CHECK_HEADERS([sys/types.h malloc/malloc.h mach/mach.h])
+AC_CHECK_HEADERS([sys/types.h sys/ioctl.h malloc/malloc.h mach/mach.h])
 if test "$ENABLE_THREADS" -eq 1 ; then
   AC_CHECK_HEADERS(pthread.h,
                    AC_SUBST(HAVE_PTHREAD, 1),