automake: create a rule for the tests

Makefile.am

@@ -251,12 +251,15 @@ tests_voices_test_LDADD   = src/libespeak-ng-test.la
 tests_voices_test_CFLAGS  = -Isrc/libespeak-ng ${AM_CFLAGS}
 tests_voices_test_SOURCES = tests/voices.c
 
-check:	tests/encoding.test tests/tokenizer.test tests/voices.test tests/languages.test
-	@echo "  TEST      tests/encoding.test" && tests/encoding.test
-	@echo "  TEST      tests/tokenizer.test" && tests/tokenizer.test
-	@echo "  TEST      tests/readclause.test" && tests/readclause.test
-	@echo "  TEST      tests/voices.test" && ESPEAK_DATA_PATH=$(PWD) tests/voices.test
-	@echo "  TEST      tests/languages.test" && tests/languages.test
+%.check: %.test
+	@echo "  TEST      $<"
+	@ESPEAK_DATA_PATH=$(PWD) $<
+
+check:	tests/encoding.check \
+	tests/tokenizer.check \
+	tests/readclause.check \
+	tests/voices.check \
+	tests/languages.check
 
 ##### phoneme data: