Fix compilation for Swift <5.5

Author: Frizlab

Sources/CLTLogger.swift

@@ -59,7 +59,7 @@ public struct CLTLogger : LogHandler {
 	 Newlines in the metadata themselves are always replaced by \n (and other special characters are escaped too).
 
 	 For now there is no option to allow multilines metadata. */
-	public enum MultilineMode : Sendable {
+	public enum MultilineMode : CLTLogger_Sendable {
 		/**
 		 The new lines in logs are replaced by the given value, the metadata are printed on the same line as the log.
 
@@ -94,7 +94,7 @@ public struct CLTLogger : LogHandler {
 		public static let `default` = Self.disallowMultiline
 	}
 
-	public struct Constants : Sendable {
+	public struct Constants : CLTLogger_Sendable {
 
 		public var logPrefix: String
 		public var multilineLogPrefix: String

Sources/DummySendable.swift

@@ -0,0 +1,8 @@
+import Foundation
+
+
+#if swift(>=5.5)
+public protocol CLTLogger_Sendable : Sendable {}
+#else
+public protocol CLTLogger_Sendable {}
+#endif