Use the correct sysroot spellings on Darwin and Linux

On Apple platforms, Clang accepts -isysroot to indicate the sysroot, while on Linux, it is --sysroot. Similarly, on Apple platforms the environment variable SDKROOT indicates the sysroot, while on Linux it is SYSROOT. rdar://47367002

Author: jakepetroules

Sources/Workspace/Destination.swift

@@ -46,6 +46,9 @@ public struct Destination {
  /// The file extension for dynamic libraries (eg. `.so` or `.dylib`)
  public let dynamicLibraryExtension: String
 
+ /// The compiler flag for specifying the sysroot (eg. `--sysroot` or `-isysroot`).
+ public let sysrootFlag: String
+
  /// Additional flags to be passed to the C compiler.
  public let extraCCFlags: [String]
 
@@ -94,7 +97,7 @@ public struct Destination {
  #if os(macOS)
  // Get the SDK.
  let sdkPath: AbsolutePath
- if let value = lookupExecutablePath(filename: getenv("SYSROOT")) {
+ if let value = lookupExecutablePath(filename: getenv("SDKROOT")) {
  sdkPath = value
  } else {
  // No value in env, so search for it.
@@ -115,6 +118,7 @@ public struct Destination {
  sdk: sdkPath,
  binDir: binDir,
  dynamicLibraryExtension: "dylib",
+ sysrootFlag: "-isysroot",
  extraCCFlags: commonArgs,
  extraSwiftCFlags: commonArgs,
  extraCPPFlags: ["-lc++"]
@@ -125,6 +129,7 @@ public struct Destination {
  sdk: .root,
  binDir: binDir,
  dynamicLibraryExtension: "so",
+ sysrootFlag: "--sysroot",
  extraCCFlags: ["-fPIC"],
  extraSwiftCFlags: [],
  extraCPPFlags: ["-lstdc++"]
@@ -187,6 +192,7 @@ extension Destination: JSONMappable {
  sdk: AbsolutePath(json.get("sdk")),
  binDir: AbsolutePath(json.get("toolchain-bin-dir")),
  dynamicLibraryExtension: json.get("dynamic-library-extension"),
+ sysrootFlag: json.get("sysroot-flag"),
  extraCCFlags: json.get("extra-cc-flags"),
  extraSwiftCFlags: json.get("extra-swiftc-flags"),
  extraCPPFlags: json.get("extra-cpp-flags")

Sources/Workspace/UserToolchain.swift

@@ -233,7 +233,7 @@ public final class UserToolchain: Toolchain {
  ] + destination.extraSwiftCFlags
 
  self.extraCCFlags = [
- "--sysroot", destination.sdk.asString
+ destination.sysrootFlag, destination.sdk.asString
  ] + destination.extraCCFlags
 
  // Compute the path of directory containing the PackageDescription libraries.

Utilities/bootstrap

@@ -1231,7 +1231,10 @@ def main():
  "SWIFTPM_BOOTSTRAP=1",
  ]
  if args.sysroot:
- env_cmd.append("SYSROOT=" + args.sysroot)
+ if platform.system() == 'Darwin':
+ env_cmd.append("SDKROOT=" + args.sysroot)
+ else:
+ env_cmd.append("SYSROOT=" + args.sysroot)
  cmd = env_cmd + [bootstrapped_product] + build_flags
 
  # Always build tests in stage2.