Remove dependency on swift-system (#448)

This dependency is unused and just unnecessarily complicates things.

CMakeLists.txt

@@ -16,7 +16,6 @@ option(BUILD_SHARED_LIBS "Build shared libraries by default" YES)
 find_package(dispatch QUIET)
 find_package(Foundation QUIET)
 find_package(Threads QUIET)
-find_package(SwiftSystem CONFIG REQUIRED)
 
 add_subdirectory(Sources)
 add_subdirectory(cmake/modules)

Package.swift

@@ -69,7 +69,6 @@ let package = Package(
             dependencies: [
               "TSCLibc",
               "TSCclibc",
-              .product(name: "SystemPackage", package: "swift-system"),
             ],
             exclude: CMakeFiles + ["README.md"],
             cxxSettings: [
@@ -110,13 +109,3 @@ let package = Package(
             exclude: ["pkgconfigInputs", "Inputs"]),
     ]
 )
-
- if ProcessInfo.processInfo.environment["SWIFTCI_USE_LOCAL_DEPS"] == nil {
-     package.dependencies += [
-         .package(url: "https://github.com/apple/swift-system.git", from: "1.1.1"),
-     ]
- } else {
-     package.dependencies += [
-         .package(path: "../swift-system"),
-     ]
- }

Sources/TSCBasic/CMakeLists.txt

@@ -56,8 +56,6 @@ target_compile_options(TSCBasic PUBLIC
   "$<$<PLATFORM_ID:Android>:SHELL:-Xcc -U_GNU_SOURCE>"
   # Ignore secure function warnings on Windows.
   "$<$<PLATFORM_ID:Windows>:SHELL:-Xcc -D_CRT_SECURE_NO_WARNINGS>")
-target_link_libraries(TSCBasic PUBLIC
-  SwiftSystem::SystemPackage)
 target_link_libraries(TSCBasic PRIVATE
   TSCclibc
   TSCLibc)

Sources/TSCBasic/FileSystem.swift

@@ -11,7 +11,6 @@
 import TSCLibc
 import Foundation
 import Dispatch
-import SystemPackage
 
 public struct FileSystemError: Error, Equatable, Sendable {
     public enum Kind: Equatable, Sendable {