Add support for Musl

Author: adam-fowler

Sources/SotoCore/Credential/ConfigFileLoader.swift

@@ -17,11 +17,6 @@ import INIParser
 import Logging
 import NIOCore
 import NIOPosix
-#if os(Linux)
-import Glibc
-#else
-import Foundation.NSString
-#endif
 
 /// Load settings from AWS credentials and profile configuration files
 /// https://docs.aws.amazon.com/cli/latest/userguide/cli-configure-files.html

Sources/SotoCore/Doc/Environment.swift

@@ -12,14 +12,18 @@
 //
 //===----------------------------------------------------------------------===//
 
-#if os(Linux)
+#if canImport(Glibc)
 import Glibc
-#else
+#elseif canImport(Musl)
+import Musl
+#elseif canImport(Darwin)
 import Darwin.C
+#else
+#error("Unsupported platform")
 #endif
 
-internal enum Environment {
-    internal static subscript(_ name: String) -> String? {
+enum Environment {
+    static subscript(_ name: String) -> String? {
         guard let value = getenv(name) else {
             return nil
         }

Sources/SotoTestUtils/Environment.swift

@@ -12,10 +12,14 @@
 //
 //===----------------------------------------------------------------------===//
 
-#if os(Linux)
+#if canImport(Glibc)
 import Glibc
-#else
+#elseif canImport(Musl)
+import Musl
+#elseif canImport(Darwin)
 import Darwin.C
+#else
+#error("Unsupported platform")
 #endif
 
 internal enum Environment {

Sources/SotoXML/Expat.swift

@@ -18,10 +18,14 @@
 //  Licensed under Apache License v2.0 http://www.apache.org/licenses/LICENSE-2.0.html
 //
 
-#if os(Linux)
+#if canImport(Glibc)
 import Glibc
-#else
+#elseif canImport(Musl)
+import Musl
+#elseif canImport(Darwin)
 import Darwin.C
+#else
+#error("Unsupported platform")
 #endif
 
 @_implementationOnly import CSotoExpat

Tests/SotoCoreTests/Credential/StaticCredential+EnvironmentTests.swift

@@ -13,10 +13,14 @@
 //===----------------------------------------------------------------------===//
 
 import XCTest
-#if os(Linux)
+#if canImport(Glibc)
 import Glibc
+#elseif canImport(Musl)
+import Musl
+#elseif canImport(Darwin)
+import Darwin.C
 #else
-import Darwin
+#error("Unsupported platform")
 #endif
 @testable import SotoCore