Fixed compilation on Linux (re. the recent addition of @inlinable).

Apparently on Linux you have to import CoreFoundation in order to _full_ access to things like `in_addr` which are otherwise part of Glibc… weird.

Sources/NetworkInterfaceInfo/IPv4Address.swift

@@ -1,15 +1,16 @@
 #if canImport(Darwin)
 import Darwin
 #else
+import CoreFoundation
 import Glibc
 
 // Annoyingly, /usr/include/netinet/in.h on Linux* is missing some constants.  [* = It's assumed here that if Darwin isn't available we're running on Linux, where Glibc is]
-let IN_CLASSD_NET = UInt32(0xf0000000)
-let INADDR_CARP_GROUP = UInt32(0xe0000012)
-let IN_LINKLOCALNETNUM = UInt32(0xa9fe0000) // This one at least makes sense - it _is_ an Apple-specific one.
-let INADDR_ALLRPTS_GROUP = UInt32(0xe0000016)
-let INADDR_PFSYNC_GROUP = UInt32(0xe00000f0)
-let INADDR_ALLMDNS_GROUP = UInt32(0xe00000fb)
+@usableFromInline let IN_CLASSD_NET = UInt32(0xf0000000)
+@usableFromInline let INADDR_CARP_GROUP = UInt32(0xe0000012)
+@usableFromInline let IN_LINKLOCALNETNUM = UInt32(0xa9fe0000) // This one at least makes sense - it _is_ an Apple-specific one.
+@usableFromInline let INADDR_ALLRPTS_GROUP = UInt32(0xe0000016)
+@usableFromInline let INADDR_PFSYNC_GROUP = UInt32(0xe00000f0)
+@usableFromInline let INADDR_ALLMDNS_GROUP = UInt32(0xe00000fb)
 #endif
 
 import Foundation