From 8da801f585dd9c534c0cbe487a3b1648036bf2fb Mon Sep 17 00:00:00 2001
From: Darren Tucker <dtucker@dtucker.net>
Date: Fri, 5 Jun 2020 13:20:10 +1000
Subject: [PATCH] Test fallthrough in OSSH_CHECK_CFLAG_COMPILE.

clang 10's -Wimplicit-fallthrough does not understand /* FALLTHROUGH */
comments and we don't use the __attribute__((fallthrough)) that it's
looking for.  This has the effect of turning off -Wimplicit-fallthrough
where it does not currently help (particularly with -Werror).  ok djm@
---
 aclocal.m4 | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/aclocal.m4 b/aclocal.m4
index 25ecc49a2..0193c3dcc 100644
--- a/aclocal.m4
+++ b/aclocal.m4
@@ -21,6 +21,16 @@ int main(int argc, char **argv) {
 	double m = l / 0.5;
 	long long int n = argc * 12345LL, o = 12345LL * (long long int)argc;
 	printf("%d %d %d %f %f %lld %lld\n", i, j, k, l, m, n, o);
+	/*
+	 * Test fallthrough behaviour.  clang 10's -Wimplicit-fallthrough does
+	 * not understand comments and we don't use the "fallthrough" attribute
+	 * that it's looking for.
+	 */
+	switch(i){
+	case 0: j += i;
+		/* FALLTHROUGH */
+	default: j += k;
+	}
 	exit(0);
 }
 	]])],