[master] 03463abf5 add back a local variable which makes flexelint grok the code

[Nils Goroll]

commit 03463abf52bad7a538d0a8b7292892055d7a41f9
Author: Nils Goroll <nils.goroll at uplex.de>
Date:   Sat Apr 4 14:32:49 2020 +0200

    add back a local variable which makes flexelint grok the code
    
    I did not understand when I committed
    119b41747f9dd3360d1fe1ea1cb181c9aefb2e81 that the local variable was
    required for flexelint to unterstand that this is not an out-of-bounds
    access.
    
    This quote of phk from the top level rant sais it all:
    
     * Do I need to tell you that static code analysis tools have a
     * really hard time coping with this, and that they give a lot of
     * false negatives which confuse people ?
    
    So true. Sorry for going a smaller but almost full circle here, I
    started with good intentions and now all that's left is the desire to
    leave the code at least a little cleaner as I found it.

diff --git a/lib/libvarnish/vsa.c b/lib/libvarnish/vsa.c
index edad67d6d..a46e8ac08 100644
--- a/lib/libvarnish/vsa.c
+++ b/lib/libvarnish/vsa.c
@@ -305,27 +305,29 @@ VSA_Build(void *d, const void *s, unsigned sal)
 {
 	struct suckaddr *sua;
 	const struct sockaddr *sa = s;
+	unsigned l;	// for flexelint
 
 	AN(d);
 	AN(s);
-	if (sal == 0 || sua_len(sa) != sal)
+	l = sua_len(sa);
+	if (l == 0 || l != sal)
 		return (NULL);
 
 	sua = d;
 
 	INIT_OBJ(sua, SUCKADDR_MAGIC);
-	switch (sal) {
+	switch (l) {
 	case sizeof sua->sa4:
-		memcpy(&sua->sa4, s, sal);
+		memcpy(&sua->sa4, s, l);
 		break;
 	case sizeof sua->sa6:
-		memcpy(&sua->sa6, s, sal);
+		memcpy(&sua->sa6, s, l);
 		break;
 	default:
 		WRONG("VSA protocol vs. size");
 	}
 #ifdef HAVE_STRUCT_SOCKADDR_SA_LEN
-	sua->sa.sa_len = (unsigned char)sal;
+	sua->sa.sa_len = (unsigned char)l;
 #endif
 	return (sua);
 }