[main] Get Swift-Foundation building against MUSL for Swift Static SDK (#848)

* Get FoundationEssentials building

Adding the missing musl imports to get FoundationEssentials building for
the Swift static SDKs again.

Also providing an option to disable building the macros. The macros
aren't necessary for building the library and will not be run as part of
the static SDK. No need to bloat the SDK or build times further. For
Swift 6, the macros should be provided by the toolchain since the
toolchain and SDK are current revlocked due to swiftmodules.

* Get FoundationInternationalization building

Adding the missing Musl imports to get FoundationInternationalization
building for the static SDK.

Author: etcwilde

Sources/FoundationEssentials/Calendar/Calendar.swift

@@ -16,6 +16,8 @@ internal import os
 import Android
 #elseif canImport(Glibc)
 import Glibc
+#elseif canImport(Musl)
+import Musl
 #elseif canImport(CRT)
 import CRT
 #elseif os(WASI)

Sources/FoundationEssentials/Calendar/Calendar_Gregorian.swift

@@ -16,6 +16,8 @@ internal import os
 import Android
 #elseif canImport(Glibc)
 import Glibc
+#elseif canImport(Musl)
+import Musl
 #elseif canImport(CRT)
 import CRT
 #elseif os(WASI)

Sources/FoundationEssentials/Data/Data+Reading.swift

@@ -22,6 +22,8 @@ import Darwin
 import Android
 #elseif canImport(Glibc)
 import Glibc
+#elseif canImport(Musl)
+import Musl
 #elseif os(Windows)
 import CRT
 import WinSDK
@@ -32,7 +34,7 @@ import WASILibc
 func _fgetxattr(_ fd: Int32, _ name: UnsafePointer<CChar>!, _ value: UnsafeMutableRawPointer!, _ size: Int, _ position: UInt32, _ options: Int32) -> Int {
 #if canImport(Darwin)
     return fgetxattr(fd, name, value, size, position, options)
-#elseif canImport(Glibc)
+#elseif canImport(Glibc) || canImport(Musl)
     return fgetxattr(fd, name, value, size)
 #else
     return -1

Sources/FoundationEssentials/Data/Data+Writing.swift

@@ -24,6 +24,8 @@ import Android
 import unistd
 #elseif canImport(Glibc)
 import Glibc
+#elseif canImport(Musl)
+import Musl
 #elseif os(Windows)
 import CRT
 import WinSDK
@@ -632,7 +634,7 @@ private func writeExtendedAttributes(fd: Int32, attributes: [String : Data]) {
             // Returns non-zero on error, but we ignore them
 #if canImport(Darwin)
             _ = fsetxattr(fd, key, valueBuf.baseAddress!, valueBuf.count, 0, 0)
-#elseif canImport(Glibc)
+#elseif canImport(Glibc) || canImport(Musl)
             _ = fsetxattr(fd, key, valueBuf.baseAddress!, valueBuf.count, 0)
 #endif
         }

Sources/FoundationEssentials/Date.swift

@@ -16,6 +16,8 @@ import Darwin
 import Bionic
 #elseif canImport(Glibc)
 import Glibc
+#elseif canImport(Musl)
+import Musl
 #elseif canImport(WinSDK)
 import WinSDK
 #elseif os(WASI)

Sources/FoundationEssentials/Decimal/Decimal+Math.swift

@@ -16,6 +16,8 @@ import Darwin
 import Android
 #elseif canImport(Glibc)
 import Glibc
+#elseif canImport(Musl)
+import Musl
 #elseif canImport(CRT)
 import CRT
 #elseif os(WASI)

Sources/FoundationEssentials/Error/CocoaError+FilePath.swift

@@ -19,6 +19,8 @@ import Darwin
 import Bionic
 #elseif canImport(Glibc)
 import Glibc
+#elseif canImport(Musl)
+import Musl
 #elseif os(Windows)
 import CRT
 import WinSDK

Sources/FoundationEssentials/Error/ErrorCodes+POSIX.swift

@@ -14,6 +14,8 @@
 @preconcurrency import Android
 #elseif canImport(Glibc)
 @preconcurrency import Glibc 
+#elseif canImport(Musl)
+@preconcurrency import Musl
 #elseif canImport(Darwin)
 @preconcurrency import Darwin
 #elseif os(Windows)

Sources/FoundationEssentials/FileManager/FileManager+Basics.swift

@@ -16,6 +16,8 @@ import Darwin
 import Android
 #elseif canImport(Glibc)
 import Glibc
+#elseif canImport(Musl)
+import Musl
 #elseif os(Windows)
 import CRT
 import WinSDK

Sources/FoundationEssentials/FileManager/FileManager+Directories.swift

@@ -23,6 +23,8 @@ import Android
 import unistd
 #elseif canImport(Glibc)
 import Glibc
+#elseif canImport(Musl)
+import Musl
 #elseif os(Windows)
 import CRT
 import WinSDK