sv.c: Silence VMS compiler warning

The result of this must be at least 0 as the type is unsigned, so
the compiler gives a warning.

1 files changed, 1 insertions, 1 deletions

diff --git a/sv.c b/sv.c
index 761addb42b..fd7e9f57a5 100644
--- a/sv.c
+++ b/sv.c
@@ -3495,7 +3495,7 @@ must_be_utf8:
 		 * set so starts from there.  Otherwise, can use memory copy to
 		 * get up to where we are now, and then start from here */
 
-		if (invariant_head <= 0) {
+		if (invariant_head == 0) {
 		    d = dst;
 		} else {
 		    Copy(s, dst, invariant_head, char);