Disable -Wmisleading-indentation warning for minizip

This was introduced recently to Clang and it fails for:

  contrib/minizip/zip.c:529:7: error: misleading indentation; statement is not part of the previous 'for'

Change-Id: Ia78b1c4222e2b46b76c579dd6f1179b7659ad337
diff --git a/BUILD.gn b/BUILD.gn
index 9819f66..43ea876 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -126,7 +126,11 @@
 
   if (is_clang) {
     # minizip uses `if ((a == b))` for some reason.
-    cflags += [ "-Wno-parentheses-equality" ]
+    cflags += [
+      "-Wno-parentheses-equality",
+      "-Wno-unknown-warning-option",
+      "-Wno-misleading-indentation",
+    ]
   }
 }