Log Message:
Update to 2.62:

* Major changes in Autoconf 2.62 (2008-04-05) [stable]
  Released by Eric Blake, based on git versions 2.61a.*.

** Many optimizations have been applied to make overall execution faster.

** Autotest now makes use of shell functions.

** config.status now uses awk instead of sed also for config headers.

   - As a side effect, AC_DEFINE and AC_DEFINE_UNQUOTED now handle multi-line
     values, i.e., backslash-newline combinations are handled correctly.
     Further, for config headers, the total size of values is not limited by
     the POSIX length limit of text lines any more, only each single line.

** New config variable `top_build_prefix'.

** New Autoconf macros:
   AC_AUTOCONF_VERSION  AC_OPENMP  AC_PATH_PROGS_FEATURE_CHECK

** AC_C_BIGENDIAN now supports universal binaries a la Mac OS X.

** AC_C_RESTRICT now prefers to #define 'restrict' to a variant spelling
   like '__restrict' if the variant spelling is available, as this is
   more likely to work when mixing C and C++ code.

** AC_CHECK_ALIGNOF's type argument T is now documented better: it must
   be a string of tokens such that "T y;" is a valid member declaration
   in a struct.

** AC_CHECK_SIZEOF now accepts objects as well as types: the general rule
   is that sizeof (X) works, then AC_CHECK_SIZEOF (X) should work.

** AC_CHECK_TYPE and AC_CHECK_TYPES now work on any C type-name; formerly,
   they did not work for function types.  In C++, they now work on any
   type-id that can be the operand of sizeof; this is similar to C,
   except it excludes anonymous struct and union types.  Formerly,
   some (but not all) C++ types involving anonymous struct and union
   were accepted, though this was not documented.

** AC_CONFIG_LINKS now prefers to link against files in the build tree
   if found, and it works to link against a file of the same name in
   the source tree, even if both trees coincide.

** AC_INIT no longer alters $@; regression introduced in 2.60.

** AC_USE_SYSTEM_EXTENSIONS now defines _ALL_SOURCE for Interix platforms.

** AS_HELP_STRING no longer underquotes its first argument; it also handles
   the case where the first argument contains single-quoted commas.
   For example, "AS_HELP_STRING([-a, [--arg[=foo]]], [bar])" produces:
     "  -a, --arg[=foo]         bar"
   Additionally, the macro now takes two additional arguments,
   indent-column and wrap-column; these should not normally be needed,
   but can be used to fine-tune how the output text is wrapped.

** AC_PROG_INSTALL now requires an install program that can install multiple
   files into a target directory.

** The command 'autoconf -' now correctly processes a file from stdin.

** 'autoreconf -m' now honors $MAKE.

** For all of the directory arguments for 'configure', such as '--prefix'
   or '--bindir', trailing slashes are stripped.  As an example, if
   tab completion in the user's shell appends trailing slashes, the
   command './configure --prefix=/usr/' will still result in an
   expanded libdir value of /usr/lib, not /usr//lib.

** `configure --help=recursive' now works in read-only trees and from
   unconfigured build trees.

** If precious variables differ only in whitespace, then the cache consistency
   check warns instead of fails, and reuses the old value.

** AT_BANNER is now documented.

** AT_SETUP now handles macro expansions properly when calculating line
   length.

** Autotest now determines $srcdir correctly.

** Testsuites built by autotest now accept a -C/--directory=DIR option
   to adjust the working directory prior to creating files.

** Autoconf now requires GNU M4 1.4.5 or later.  Earlier versions of M4 have
   a bug in macro tracing that interferes with the interaction between
   Autoconf and Automake.  GNU M4 1.4.11 or later is recommended.  The
   configure search for a working M4 is improved.

** For portability with the eventual M4 2.0, macros should no longer use
   anything larger than $9 to refer to arguments.

** Documentation for m4sugar is improved.

   - The following macros were previously available as undocumented
     interfaces; the macros are now documented as stable interfaces.

     __oline__  m4_assert  m4_bmatch  m4_bpatsubsts  m4_car  m4_case
     m4_cdr  m4_default  m4_divert_once  m4_divert_pop  m4_divert_push
     m4_divert_text  m4_do  m4_errprintn  m4_fatal  m4_flatten
     m4_ifndef  m4_ifset  m4_ifval  m4_ifvaln  m4_location
     m4_n  m4_shiftn  m4_strip  m4_warn

   - The following macros were previously available as undocumented
     interfaces, but had bug fixes or semantic changes as part of this
     release.  Packages that relied on the undocumented behavior
     should be analyzed to make sure they will still work with the
     new documented behavior.

     m4_cmp  m4_list_cmp  m4_join  m4_map  m4_map_sep  m4_sign
     m4_text_box  m4_text_wrap  m4_version_compare

   - The m4_wrap macro used to have unspecified order, but now
     guarantees FIFO order.  m4_wrap_lifo was added to guarantee LIFO
     order.

   - Packages using the undocumented m4sugar macro m4_PACKAGE_VERSION
     should consider using the new AC_AUTOCONF_VERSION instead.

   - m4sugar macros that are not documented in the manual are still
     deemed experimental, and should not be used outside of Autoconf.

** The m4sugar macros m4_append and m4_append_uniq, first documented in
   2.60, have been fixed to treat both the string and the separator
   arguments consistently with regards to quoting.  Prior to this fix,
   m4_append_uniq could mistakenly duplicate entries if the expansion
   of the separator resulted in a different string (for example, if it
   contained quotes, a comma, or a macro name).  However, it means
   that programs previously using
     m4_append([name], [string], [[, ]])
   are now using a four-character separator instead of the intended
   comma and space.  If you need portability to earlier versions of
   Autoconf, you can insert the following snippet after AC_INIT but
   before any other macro expansions, to enforce the new semantics:
     m4_pushdef([m4_append], [m4_define([$1],
	   m4_ifdef([$1], [m4_defn([$1])[$3]])[$2])])
   Additionally, m4_append_uniq now takes optional parameters that can
   be used to take action depending on whether anything was appended,
   and warns if a non-empty separator occurs within the string being
   appended, since that can lead to duplicates.

** The following m4sugar macros are new:
   m4_append_uniq_w  m4_apply  m4_combine  m4_cond  m4_count
   m4_dquote_elt  m4_echo  m4_expand  m4_ignore  m4_make_list  m4_max
   m4_min  m4_newline  m4_shift2  m4_shift3  m4_unquote  m4_wrap_lifo

** Warnings are now generated by default when an installer invokes
   'configure' with an unknown --enable-* or --with-* option.
   These warnings can be disabled with the new AC_DISABLE_OPTION_CHECKING
   macro, or by invoking 'configure' with --disable-option-checking.

** Existing obsolete macros
   The documentation for the following macros is adjusted to make it
   more clear that they have previously been marked obsolete, as their
   functionality can be accomplished by other macros.  We have no
   current plans to remove them from Autoconf.

     AC_ENABLE  AC_STRUCT_ST_BLKSIZE  AC_STRUCT_ST_RDEV  AC_WITH

** Newly obsolete macros
   The following macros have been marked obsolete, as they only
   perform a subset of AC_USE_SYSTEM_EXTENSIONS.  We have no current
   plans to remove them.

     AC_AIX  AC_GNU_SOURCE  AC_ISC_POSIX  AC_MINIX

** AC_C_LONG_DOUBLE is obsolescent.
   The documentation now says that AC_C_LONG_DOUBLE is obsolescent: it
   tests for problems that are so old that it is no longer of
   practical importance on current systems.  New programs need not use
   AC_C_LONG_DOUBLE.  We have no current plans to remove it.

** AC_DIAGNOSE, AC_WARNING, and AC_FATAL are obsolescent.
   The documentation now favors the use of M4sugar macros m4_warn and
   m4_fatal, since the naming makes it more obvious that the
   diagnostics are associated with M4 expansion (ie. when running
   `autoconf'), and offers less confusion with the AC_MSG_ERROR,
   AC_MSG_FAILURE, and AC_MSG_WARN macros which manage diagnostics
   when running `configure'.  We have no current plans to remove these
   macros.

* Major changes in Autoconf 2.61a (2006-12-11)

** AC_FUNC_FSEEKO was broken in 2.61; it didn't make fseeko and ftello visible
   on many platforms.  This has been fixed.

** AC_FUNC_SETVBUF_REVERSED is now obsolete.  It is still defined for backward
   compatibility but it does nothing.  The macro was already
   obsolescent, as the last systems to have the problem were those
   based on SVR2, which became obsolete in 1987.  The macro had bugs
   on some modern systems and could no longer be maintained reliably
   due to lack of ancient systems to test it on.

** config.status now uses awk instead of sed for most substitutions, for speed.

   - As a side effect multi-line values of substituted variables no
     longer have a small limit in total size, though for portability
     each line should not exceed the POSIX length limit for text lines.

   - It is now documented that Makefile.in should not contain
     overlapping variable occurrences, e.g., @VAR1@VAR2@.
     Autoconf's behavior was always iffy in such cases, and the
     awk implementation has changed the behavior.

** Many uses of 'echo' have been rewritten so that Autoconf-generated
   scripts have fewer problems with strings or file names containing
   embedded special characters such as backslash or leading "-".  This
   was implemented by using `printf '%s\n' "$foo"' instead of `echo
   "$foo"' when printf works.  Due to the implementation technique
   used, Autoconf-generated scripts now run considerably more slowly
   on ancient implementations lacking printf.  However, this should
   not be a problem, since Autoconf-generated scripts in practice
   invariably find a more-modern shell these days.