[PATCH] t/README: Add a note about running commands under valgrind

["Carlos Martín Nieto" <cmn@elego.de>]

The test suite runs valgrind with certain options activated. Add a
note saying how to run commands under the same conditions as the test
suite does.

Signed-off-by: Carlos Martín Nieto <cmn@elego.de>
---

 As Jeff pointed out, the test suite does use --leak-check=no. I was
using valgrind manually as I was chasing a different error that does
show up. How about adding this to the README?

 t/README |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)

diff --git a/t/README b/t/README
index 78c9e65..2a73fc3 100644
--- a/t/README
+++ b/t/README
@@ -98,6 +98,13 @@ appropriately before running "make".
 	not see any output, this option implies --verbose.  For
 	convenience, it also implies --tee.
 
+	*NOTE*: As the git process is short-lived and some errors are
+	not interesting, valgrind is run with (among others) the
+	option --leak-check=no. In order to run a single command under
+	the same conditions manually, you should set GIT_VALGRIND to
+	point to the 't/valgrind/' directory and use the commands
+	under 't/valgrind/bin/'.
+
 --tee::
 	In addition to printing the test output to the terminal,
 	write it to files named 't/test-results/$TEST_NAME.out'.
-- 
1.7.4.1