Use Bionic module from new Android overlay in Swift 6 instead

The new module and overlay were merged into Swift 6 in swiftlang/swift#74758.

Author: finagolfin

Sources/VariadicsGenerator/VariadicsGenerator.swift

@@ -18,6 +18,8 @@ import Darwin
 import Glibc
 #elseif os(Windows)
 import CRT
+#elseif canImport(Bionic)
+import Bionic
 #endif
 
 // (T), (T)