Add ZT_NO_UNALIGNED_ACCESS for ARMv6/7 on FreeBSD

Unaligned access caused SIGBUS errors on ARMv6 and ARMv7 targets under FreeBSD.

This was also the cause of the repeating TAP devices. Each time the SIGBUS happened, the service would auto-restart itself, create a new TAP device, and then crash again.

The particular place causing the SIGBUS was:
https://github.com/zerotier/ZeroTierOne/blob/master/node/Utils.hpp#L695

make-bsd.mk

@@ -65,7 +65,7 @@ ifeq ($(CC_MACH),armhf)
 endif
 ifeq ($(CC_MACH),armv6)
 	ZT_ARCHITECTURE=3
-	override DEFS+=-DZT_NO_TYPE_PUNNING
+	override DEFS+=-DZT_NO_TYPE_PUNNING -DZT_NO_UNALIGNED_ACCESS
 	ZT_USE_ARM32_NEON_ASM_SALSA2012=1
 endif
 ifeq ($(CC_MACH),armv6zk)
@@ -80,7 +80,7 @@ ifeq ($(CC_MACH),armv6kz)
 endif
 ifeq ($(CC_MACH),armv7)
 	ZT_ARCHITECTURE=3
-	override DEFS+=-DZT_NO_TYPE_PUNNING -DZT_AES_NO_ACCEL
+	override DEFS+=-DZT_NO_TYPE_PUNNING -DZT_AES_NO_ACCEL -DZT_NO_UNALIGNED_ACCESS
 	ZT_USE_ARM32_NEON_ASM_SALSA2012=1
 endif
 ifeq ($(CC_MACH),arm64)