mtest: add support for hard errors

Hard errors also come from the GNU Automake test protocol.  They happen when
e.g., the set-up of a test case scenario fails, or when some
other unexpected or highly undesirable condition is encountered.

TAP will use them for parse errors too.  Add them to the exitcode protocol
first.

2 files changed, 7 insertions, 0 deletions

diff --git a/test cases/failing test/4 hard error/main.c b/test cases/failing test/4 hard error/main.c
new file mode 100644
index 0000000..a1e705a
--- /dev/null
+++ b/test cases/failing test/4 hard error/main.c
@@ -0,0 +1,3 @@
+int main(void) {
+    return 99;
+}
diff --git a/test cases/failing test/4 hard error/meson.build b/test cases/failing test/4 hard error/meson.build
new file mode 100644
index 0000000..6979b04
--- /dev/null
+++ b/test cases/failing test/4 hard error/meson.build
@@ -0,0 +1,4 @@
+project('trivial', 'c')
+
+# Exit code 99 even overrides should_fail
+test('My Test', executable('main', 'main.c'), should_fail: true)