[PATCH] docs: mention traditional awk limitation

[Eric Blake]

* doc/autoconf.texi (Limitations of Usual Tools) <awk>: Mention
that traditional awk lacks ENVIRON.  Add reference to awk manual.
(Particular Programs) <AC_PROG_AWK>: Add reference to awk section.
Reported by Ralf Wildenhues.

Signed-off-by: Eric Blake <address@hidden>
---

> Pointing to the gawk.info node "Language History" is probably a good
> idea, too, its sub-nodes have lots more details.

Yeah, that does sound nice.  Here's the final version I'm pushing.

 ChangeLog         |    8 ++++++++
 doc/autoconf.texi |   10 ++++++++--
 2 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 73be221..77d513c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2010-09-08  Eric Blake  <address@hidden>
+
+       docs: mention traditional awk limitation
+       * doc/autoconf.texi (Limitations of Usual Tools) <awk>: Mention
+       that traditional awk lacks ENVIRON.  Add reference to awk manual.
+       (Particular Programs) <AC_PROG_AWK>: Add reference to awk section.
+       Reported by Ralf Wildenhues.
+
 2010-09-07  Eric Blake  <address@hidden>

        docs: mention bash vs. POSIXLY_CORRECT
diff --git a/doc/autoconf.texi b/doc/autoconf.texi
index 15639d9..24c6e14 100644
--- a/doc/autoconf.texi
+++ b/doc/autoconf.texi
@@ -3915,6 +3915,9 @@ Particular Programs
 It tries @code{gawk} first because that is reported to be the
 best implementation.  The result can be overridden by setting the
 variable @code{AWK} or the cache variable @code{ac_cv_prog_AWK}.
+
+Using this macro is sufficient to avoid the pitfalls of traditional
address@hidden (@pxref{awk, , Limitations of Usual Tools}).
 @end defmac

 @defmac AC_PROG_GREP
@@ -17732,6 +17735,7 @@ Limitations of Usual Tools
 @c This table includes things like address@hidden (|)', so we can't
 @c use @table @command.
 @table @asis
address@hidden
 @item @command{awk}
 @c ----------------
 @prindex @command{awk}
@@ -17828,7 +17832,8 @@ Limitations of Usual Tools
 conform to Posix.  Nowadays @code{AC_PROG_AWK} (@pxref{Particular
 Programs}) finds you an Awk that doesn't have these problems, but if
 for some reason you prefer not to use @code{AC_PROG_AWK} you may need to
-address them.
+address them.  For more detailed descriptions, see @ref{Language
+History, , @command{awk} language history, gawk, GNU Awk User's Guide}.

 Traditional Awk does not support multidimensional arrays or user-defined
 functions.
@@ -17845,7 +17850,8 @@ Limitations of Usual Tools
 @address@hidden@var{b}:@var{c}}, @address@hidden, @address@hidden@var{b}},
 or @address@hidden@var{b}}.

-Traditional Awk does not support the predefined @code{CONVFMT} variable.
+Traditional Awk does not support the predefined @code{CONVFMT} or
address@hidden variables.

 Traditional Awk supports only the predefined functions @code{exp}, 
@code{index},
 @code{int}, @code{length}, @code{log}, @code{split}, @code{sprintf},
-- 
1.7.2.2