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Refresh autoconf-archive m4 scripts

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1 parent 1ff9c60 commit 4130e1972d001143e5e9f3c6b65f2a6f9524169e @atgreen atgreen committed Feb 3, 2012
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@@ -40,3 +40,4 @@ m68k-patches
unlikely
amiga
alpha
+autoconf-archive-update
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@@ -0,0 +1,92 @@
+# mmap(2) blacklisting. Some platforms provide the mmap library routine
+# but don't support all of the features we need from it.
+AC_DEFUN([AC_FUNC_MMAP_BLACKLIST],
+[
+AC_CHECK_HEADER([sys/mman.h],
+ [libffi_header_sys_mman_h=yes], [libffi_header_sys_mman_h=no])
+AC_CHECK_FUNC([mmap], [libffi_func_mmap=yes], [libffi_func_mmap=no])
+if test "$libffi_header_sys_mman_h" != yes \
+ || test "$libffi_func_mmap" != yes; then
+ ac_cv_func_mmap_file=no
+ ac_cv_func_mmap_dev_zero=no
+ ac_cv_func_mmap_anon=no
+else
+ AC_CACHE_CHECK([whether read-only mmap of a plain file works],
+ ac_cv_func_mmap_file,
+ [# Add a system to this blacklist if
+ # mmap(0, stat_size, PROT_READ, MAP_PRIVATE, fd, 0) doesn't return a
+ # memory area containing the same data that you'd get if you applied
+ # read() to the same fd. The only system known to have a problem here
+ # is VMS, where text files have record structure.
+ case "$host_os" in
+ vms* | ultrix*)
+ ac_cv_func_mmap_file=no ;;
+ *)
+ ac_cv_func_mmap_file=yes;;
+ esac])
+ AC_CACHE_CHECK([whether mmap from /dev/zero works],
+ ac_cv_func_mmap_dev_zero,
+ [# Add a system to this blacklist if it has mmap() but /dev/zero
+ # does not exist, or if mmapping /dev/zero does not give anonymous
+ # zeroed pages with both the following properties:
+ # 1. If you map N consecutive pages in with one call, and then
+ # unmap any subset of those pages, the pages that were not
+ # explicitly unmapped remain accessible.
+ # 2. If you map two adjacent blocks of memory and then unmap them
+ # both at once, they must both go away.
+ # Systems known to be in this category are Windows (all variants),
+ # VMS, and Darwin.
+ case "$host_os" in
+ vms* | cygwin* | pe | mingw* | darwin* | ultrix* | hpux10* | hpux11.00)
+ ac_cv_func_mmap_dev_zero=no ;;
+ *)
+ ac_cv_func_mmap_dev_zero=yes;;
+ esac])
+
+ # Unlike /dev/zero, the MAP_ANON(YMOUS) defines can be probed for.
+ AC_CACHE_CHECK([for MAP_ANON(YMOUS)], ac_cv_decl_map_anon,
+ [AC_TRY_COMPILE(
+[#include <sys/types.h>
+#include <sys/mman.h>
+#include <unistd.h>
+
+#ifndef MAP_ANONYMOUS
+#define MAP_ANONYMOUS MAP_ANON
+#endif
+],
+[int n = MAP_ANONYMOUS;],
+ ac_cv_decl_map_anon=yes,
+ ac_cv_decl_map_anon=no)])
+
+ if test $ac_cv_decl_map_anon = no; then
+ ac_cv_func_mmap_anon=no
+ else
+ AC_CACHE_CHECK([whether mmap with MAP_ANON(YMOUS) works],
+ ac_cv_func_mmap_anon,
+ [# Add a system to this blacklist if it has mmap() and MAP_ANON or
+ # MAP_ANONYMOUS, but using mmap(..., MAP_PRIVATE|MAP_ANONYMOUS, -1, 0)
+ # doesn't give anonymous zeroed pages with the same properties listed
+ # above for use of /dev/zero.
+ # Systems known to be in this category are Windows, VMS, and SCO Unix.
+ case "$host_os" in
+ vms* | cygwin* | pe | mingw* | sco* | udk* )
+ ac_cv_func_mmap_anon=no ;;
+ *)
+ ac_cv_func_mmap_anon=yes;;
+ esac])
+ fi
+fi
+
+if test $ac_cv_func_mmap_file = yes; then
+ AC_DEFINE(HAVE_MMAP_FILE, 1,
+ [Define if read-only mmap of a plain file works.])
+fi
+if test $ac_cv_func_mmap_dev_zero = yes; then
+ AC_DEFINE(HAVE_MMAP_DEV_ZERO, 1,
+ [Define if mmap of /dev/zero works.])
+fi
+if test $ac_cv_func_mmap_anon = yes; then
+ AC_DEFINE(HAVE_MMAP_ANON, 1,
+ [Define if mmap with MAP_ANON(YMOUS) works.])
+fi
+])
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