vala tests: add missing 'valac' requirement, and other minor fixlets

See also automake bug#10575.

* tests/vala-mix.test ($required): Add 'valac'; this will avoid
spurious failures on systems lacking a Vala compiler.
Add some explicative comments for a couple of non-obvious make
calls.
Make grepping of "make -n" slightly stricter, to avoid potential
false positives.

diff --git a/tests/vala-mix.test b/tests/vala-mix.test
index f597a7f..73a07d9 100755 (executable)
--- a/tests/vala-mix.test
+++ b/tests/vala-mix.test
@@ -16,7 +16,7 @@
 
 # Vala sources and C sources in the same program.  Functional test.
 
-required='cc GNUmake'
+required='valac cc GNUmake'
 . ./defs || Exit 1
 
 set -e
@@ -96,8 +96,9 @@ have_generated_files ()
 # C files.
 have_generated_files
 
+# Remake rules are not uselessly triggered.
 $MAKE -q
-$MAKE -n | grep stamp && Exit 1
+$MAKE -n | $FGREP vala.stamp && Exit 1
 
 # Check the distribution.
 $MAKE distcheck