WIP: Allow Clang executable targets to be linked into unit test targets as well. This implementation is currently a hack since it's not at all clear that we'll want to allow random types of products to link against executable targets.

Author: abertelrud

Sources/Build/BuildPlan.swift

@@ -258,7 +258,8 @@ public final class ClangTargetBuildDescription {
         self.derivedSources = Sources(paths: [], root: tempsPath.appending(component: "DerivedSources"))
 
         // Try computing modulemap path for a C library.  This also creates the file in the file system, if needed.
-        if target.type == .library {
+        // FIXME: Adding .executable here is probably not right, but is needed in order to test Clang executables.
+        if target.type == .library || target.type == .executable {
             // If there's a custom module map, use it as given.
             if case .custom(let path) = clangTarget.moduleMapType {
                 self.moduleMap = path
@@ -1690,7 +1691,8 @@ public class BuildPlan {
         // depends on.
         for case .target(let dependency, _) in swiftTarget.target.recursiveDependencies(satisfying: buildEnvironment) {
             switch dependency.underlyingTarget {
-            case let underlyingTarget as ClangTarget where underlyingTarget.type == .library:
+            // FIXME: Adding .executable here is probably not right, but is needed in order to test Clang executables.
+            case let underlyingTarget as ClangTarget where underlyingTarget.type == .library || underlyingTarget.type == .executable:
                 guard case let .clang(target)? = targetMap[dependency] else {
                     fatalError("unexpected clang target \(underlyingTarget)")
                 }