[PATCH] Document the grep workaround.

[Eric Blake]

* doc/autoconf.texi (Limitations of Usual Tools) <grep>: Document
the bug.

Signed-off-by: Eric Blake <address@hidden>
---
 ChangeLog         |    6 ++++++
 doc/autoconf.texi |    4 ++++
 2 files changed, 10 insertions(+), 0 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 6a614bc..fd7d068 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2010-05-12  Eric Blake  <address@hidden>
+
+       Document the grep workaround.
+       * doc/autoconf.texi (Limitations of Usual Tools) <grep>: Document
+       the bug.
+
 2010-05-12  Mark Hessling  <address@hidden>  (tiny change)

        Work around QNX4 grep bug.
diff --git a/doc/autoconf.texi b/doc/autoconf.texi
index 39e11a5..ff62eac 100644
--- a/doc/autoconf.texi
+++ b/doc/autoconf.texi
@@ -17829,6 +17829,10 @@ Limitations of Usual Tools
 doesn't exist) of @code{grep} to @file{/dev/null}.  Check the exit
 status of @code{grep} to determine whether it found a match.

+The QNX4 implementation fails to count lines with @code{grep -c '$'},
+but works with @code{grep -c '^'}.  Another alternative for counting
+lines is to use @code{wc -l}.
+
 Some traditional @command{grep} implementations do not work on long
 input lines.  On AIX the default @code{grep} silently truncates long
 lines on the input before matching.
-- 
1.7.0.1