AC_DEFUN([AC_NEED_DEV_ZERO_FOR_MMAP],
[AC_CACHE_CHECK([if /dev/zero is needed for mmap],
ac_cv_need_dev_zero_for_mmap,
-[if test "$llvm_cv_os_type" == "Interix" ; then
+[if test "$llvm_cv_os_type" = "Interix" ; then
ac_cv_need_dev_zero_for_mmap=yes
else
ac_cv_need_dev_zero_for_mmap=no