[PATCH 0/7] AS_LITERAL_IF speedups

[Eric Blake]

I've been sitting on these patches since March, and finally had
enough time to polish them off and verify that the testsuite
passes after every single one of them.  I know that Ralf reviewed
the earlier versions and had some nits, which I have folded in
to these patches.  I went ahead and pushed these:

Eric Blake (7):
  Optimize AC_DEFINE.
  Add AS_LITERAL_WORD_IF.
  Use AS_LITERAL_WORD_IF as appropriate.
  Add optional argument to AS_LITERAL_IF.
  Add tests for AS_BOX.
  Use new AS_LITERAL_IF argument when appropriate.
  Optimize AS_BOX.

 ChangeLog                  |   58 +++++++++++++++++++++
 NEWS                       |    9 +++
 doc/autoconf.texi          |   65 ++++++++++++++++++++----
 lib/autoconf/autoheader.m4 |    2 +-
 lib/autoconf/general.m4    |   14 +++---
 lib/autoconf/libs.m4       |    2 +-
 lib/autoconf/status.m4     |    2 +-
 lib/autoconf/types.m4      |   22 ++++++---
 lib/m4sugar/m4sh.m4        |  120 ++++++++++++++++++++++++++++++--------------
 lib/m4sugar/m4sugar.m4     |    6 +-
 tests/m4sh.at              |   84 +++++++++++++++++++++++++++----
 tests/m4sugar.at           |   24 +++++++++
 12 files changed, 329 insertions(+), 79 deletions(-)