Fix forwarding of -ld-path

The Clang linker driver spells this as --ld-path so we can't forward the argument wholesale anymore, since we spell it -ld-path.

(cherry picked from commit 9a357ee)

# Conflicts:
#	Sources/SwiftDriver/Jobs/WindowsToolchain+LinkerSupport.swift

Author: kabiroberai

Sources/SwiftDriver/Jobs/DarwinToolchain+LinkerSupport.swift

@@ -181,7 +181,9 @@ extension DarwinToolchain {
       commandLine.appendFlag("-fuse-ld=\(arg.asSingle)")
     }
 
-    try commandLine.appendLast(.ldPath, from: &parsedOptions)
+    if let arg = parsedOptions.getLastArgument(.ldPath)?.asSingle {
+      commandLine.append(.joinedOptionAndPath("--ld-path=", try VirtualPath(path: arg)))
+    }
 
     let fSystemArgs = parsedOptions.arguments(for: .F, .Fsystem)
     for opt in fSystemArgs {

Sources/SwiftDriver/Jobs/GenericUnixToolchain+LinkerSupport.swift

@@ -101,7 +101,9 @@ extension GenericUnixToolchain {
         }
       }
 
-      try commandLine.appendLast(.ldPath, from: &parsedOptions)
+      if let arg = parsedOptions.getLastArgument(.ldPath)?.asSingle {
+        commandLine.append(.joinedOptionAndPath("--ld-path=", try VirtualPath(path: arg)))
+      }
 
       // Configure the toolchain.
       //

Sources/SwiftDriver/Jobs/WebAssemblyToolchain+LinkerSupport.swift

@@ -43,7 +43,9 @@ extension WebAssemblyToolchain {
         commandLine.appendFlag("-fuse-ld=\(linkerArg)")
       }
 
-      try commandLine.appendLast(.ldPath, from: &parsedOptions)
+      if let arg = parsedOptions.getLastArgument(.ldPath)?.asSingle {
+        commandLine.append(.joinedOptionAndPath("--ld-path=", try VirtualPath(path: arg)))
+      }
 
       // Configure the toolchain.
       //