Move arch to a global variable

Author: danny1113

Sources/LinuxPlatform/Linux.swift

@@ -382,13 +382,7 @@ public struct Linux: Platform {
     }
 
     public func getExecutableName() -> String {
-#if arch(x86_64)
-        let arch = "x86_64"
-#elseif arch(arm64)
-        let arch = "aarch64"
-#else
-        fatalError("Unsupported processor architecture")
-#endif
+        let arch = cpuArch
 
         return "swiftly-\(arch)-unknown-linux-gnu"
     }

Sources/SwiftlyCore/HTTPClient.swift

@@ -295,17 +295,7 @@ public struct SwiftlyHTTPClient {
         limit: Int? = nil,
         filter: ((ToolchainVersion.StableRelease) -> Bool)? = nil
     ) async throws -> [ToolchainVersion.StableRelease] {
-        let arch = if a == nil {
-#if arch(x86_64)
-            "x86_64"
-#elseif arch(arm64)
-            "aarch64"
-#else
-            #error("Unsupported processor architecture")
-#endif
-        } else {
-            a!
-        }
+        let arch = a ?? cpuArch
 
         let url = "https://www.swift.org/api/v1/install/releases.json"
         let swiftOrgReleases: [SwiftOrgRelease] = try await self.getFromJSON(url: url, type: [SwiftOrgRelease].self)
@@ -359,17 +349,7 @@ public struct SwiftlyHTTPClient {
         limit: Int? = nil,
         filter: ((ToolchainVersion.Snapshot) -> Bool)? = nil
     ) async throws -> [ToolchainVersion.Snapshot] {
-        let arch = if a == nil {
-#if arch(x86_64)
-            "x86_64"
-#elseif arch(arm64)
-            "aarch64"
-#else
-            #error("Unsupported processor architecture")
-#endif
-        } else {
-            a!
-        }
+        let arch = a ?? cpuArch
 
         let platformName = if platform.name == PlatformDefinition.macOS.name {
             "macos"

Sources/SwiftlyCore/SwiftlyCore.swift

@@ -51,3 +51,11 @@ public func readLine(prompt: String) -> String? {
     }
     return provider.readLine()
 }
+
+#if arch(x86_64)
+    public let cpuArch = "x86_64"
+#elseif arch(arm64)
+    public let cpuArch = "aarch64"
+#else
+    #error("Unsupported processor architecture")
+#endif