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