www/firefox: browser.tabs.remote.autostart=false may stop working in future

[Jan Beich <jbeich%FreeBSD.org@localhost>]

Firefox deprecated single process mode since 68.0 (ESR) but PkgSrc isn't
affected yet as MOZILLA_OFFICIAL isn't defined. Consider limiting the
workaround to NetBSD kernel, disabling CrossProcessSemaphore like
OpenBSD or fixing the actual issue.

https://www.mail-archive.com/dev-platform%lists.mozilla.org@localhost/msg27644.html

diff --git a/modules/libpref/init/all.js b/modules/libpref/init/all.js
index 8a9e2435ba9d..946d8d71e159 100644
--- a/modules/libpref/init/all.js
+++ b/modules/libpref/init/all.js
@@ -5039,7 +5039,7 @@ pref("layers.max-active", -1);
 // 0  -> full-tilt mode: Recomposite even if not transaction occured.
 pref("layers.offmainthreadcomposition.frame-rate", -1);
 
-#if defined(XP_MACOSX) || defined (OS_OPENBSD)
+#if defined(XP_MACOSX) || defined(OS_NETBSD) || defined(OS_OPENBSD)
 pref("layers.enable-tiles", true);
 #else
 pref("layers.enable-tiles", false);