1#
2# When allocating RWX memory, check whether we need to use /dev/zero
3# as the file descriptor or not.
4#
5AC_DEFUN([AC_NEED_DEV_ZERO_FOR_MMAP],
6[AC_CACHE_CHECK([if /dev/zero is needed for mmap],
7ac_cv_need_dev_zero_for_mmap,
8[if test "$llvm_cv_os_type" = "Interix" ; then
9   ac_cv_need_dev_zero_for_mmap=yes
10 else
11   ac_cv_need_dev_zero_for_mmap=no
12 fi
13])
14if test "$ac_cv_need_dev_zero_for_mmap" = yes; then
15  AC_DEFINE([NEED_DEV_ZERO_FOR_MMAP],[1],
16   [Define if /dev/zero should be used when mapping RWX memory, or undefine if its not necessary])
17fi])
18