--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/autoconf/m4/func_mmap_file.m4	Thu Dec 12 13:56:28 2013 +0900
@@ -0,0 +1,26 @@
+#
+# Check for the ability to mmap a file.  
+#
+AC_DEFUN([AC_FUNC_MMAP_FILE],
+[AC_CACHE_CHECK(for mmap of files,
+ac_cv_func_mmap_file,
+[ AC_LANG_PUSH([C])
+  AC_RUN_IFELSE([
+    AC_LANG_PROGRAM([[
+#include <sys/types.h>
+#include <sys/mman.h>
+#include <fcntl.h>
+]],[[
+  int fd;
+  fd = creat ("foo",0777); 
+  fd = (int) mmap (0, 1, PROT_READ, MAP_SHARED, fd, 0);
+  unlink ("foo"); 
+  return (fd != (int) MAP_FAILED);]])],
+  [ac_cv_func_mmap_file=yes],[ac_cv_func_mmap_file=no],[ac_cv_func_mmap_file=no])
+  AC_LANG_POP([C])
+])
+if test "$ac_cv_func_mmap_file" = yes; then
+   AC_DEFINE([HAVE_MMAP_FILE],[],[Define if mmap() can map files into memory])
+   AC_SUBST(MMAP_FILE,[yes])
+fi
+])