Add required opt-ins for using commonized functions with different bit width integers

Author: ilya-g

core/linux/src/TimeZoneNative.kt

@@ -58,6 +58,7 @@ internal actual class RegionTimeZone(private val tzid: TimeZoneRules, actual ove
     actual override fun offsetAtImpl(instant: Instant): UtcOffset = tzid.infoAtInstant(instant)
 }
 
+@OptIn(UnsafeNumber::class)
 internal actual fun currentTime(): Instant = memScoped {
     val tm = alloc<timespec>()
     val error = clock_gettime(CLOCK_REALTIME, tm.ptr)

core/nix/src/internal/filesystem.kt

@@ -3,7 +3,7 @@
  * Use of this source code is governed by the Apache 2.0 License that can be found in the LICENSE.txt file.
  */
 
-@file:OptIn(ExperimentalForeignApi::class)
+@file:OptIn(ExperimentalForeignApi::class, UnsafeNumber::class)
 package kotlinx.datetime.internal
 
 import kotlinx.cinterop.*