[openssh-portable] Temporarily disable `-Wsizeof-array-div` warnings

Clang introduced a new warning that is raised when we
attempt to check the size of an array through sizeof() division. If the
type of the sizeof() in the divisor is not the same as that of the array
element, a warning is raised.

BUG: 36439
Change-Id: I83adf996591206744cb7c4e1a94b786de18043ac
diff --git a/BUILD.gn b/BUILD.gn
index 432fc5b9..732c409 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -245,6 +245,14 @@
 
 config("openbsd-compat-config") {
   include_dirs = [ "openbsd-compat" ]
+  cflags = [
+    # TODO(36439): Clang introduced a new warning that is raised when we
+    # attempt to check the size of an array through sizeof() division. If the
+    # type of the sizeof() in the divisor is not the same as that of the array
+    # element, a warning is raised.
+    "-Wno-unknown-warning-option",
+    "-Wno-sizeof-array-div",
+  ]
 }
 
 source_set("openbsd-compat") {