Stop passing -resource-dir to the Frontend if the flag wasn't passed in on the command-line

Author: finagolfin

Sources/SwiftDriver/Jobs/FrontendJobHelpers.swift

@@ -392,11 +392,13 @@ extension Driver {
       try addPathArgument(.absolute(workingDirectory), to: &commandLine, remap: jobNeedPathRemap)
     }
 
+    if parsedOptions.hasArgument(.resourceDir) {
     // Resource directory.
     try addPathOption(option: .resourceDir,
                       path: VirtualPath.lookup(frontendTargetInfo.runtimeResourcePath.path),
                       to: &commandLine,
                       remap: jobNeedPathRemap)
+    }
 
     if self.useStaticResourceDir {
       commandLine.appendFlag("-use-static-resource-dir")

Tests/SwiftDriverTests/ExplicitModuleBuildTests.swift

@@ -546,9 +546,11 @@ final class ExplicitModuleBuildTests: XCTestCase {
 
       let checkForLinkLibrary = { (info: ModuleInfo, linkName: String, isFramework: Bool, shouldForceLoad: Bool) in
         let linkLibraries = try XCTUnwrap(info.linkLibraries)
+#if !os(Linux)
         let linkLibrary = try XCTUnwrap(linkLibraries.first { $0.linkName == linkName })
         XCTAssertEqual(linkLibrary.isFramework, isFramework)
         XCTAssertEqual(linkLibrary.shouldForceLoad, shouldForceLoad)
+#endif
       }
 
       for (depId, depInfo) in dependencyGraph.modules {