docs: issues with configure substitutions in TESTS

Motivated by automake bug#14019.

* doc/automake.texi: Currently, when the parallel test harness is in use,
configure substitutions in TESTS definitions can only work if they expand
to tests that ends with a suffix listed in TEST_EXTENSIONS.  Document this
limitation.

Signed-off-by: Stefano Lattarini <stefano.lattarini@gmail.com>

diff --git a/doc/automake.texi b/doc/automake.texi
index d3aefb5..e52cc3a 100644 (file)
--- a/doc/automake.texi
+++ b/doc/automake.texi
@@ -9089,6 +9089,12 @@ followed by any number of alphabetic characters.
 For example, @samp{.sh}, @samp{.T} and @samp{.t1} are valid extensions,
 while @samp{.x-y}, @samp{.6c} and @samp{.t.1} are not.
 
+@cindex Configure substitutions in @code{TESTS}
+It is important to note that, due to current limitations (unlikely to be
+lifted), configure substitutions in the definition of @code{TESTS} can
+only work if they will expand to a list of tests that have a suffix listed
+in @code{TEST_EXTENSIONS}.
+
 @vindex _LOG_COMPILE
 @vindex _LOG_COMPILER
 @vindex _LOG_FLAGS