Fix two small issues with handling of plugin triples

- We were not stringently using version-less triples in all comparisons
- We were not merging the supported triples of all executable info entries into the final `toolNamesToTriples` which could lead to incorrect errors about unsupported platforms

rdar://101096803

Author: neonichu

Sources/SPMBuildCore/BinaryTarget+Extensions.swift

@@ -74,13 +74,13 @@ extension BinaryTarget {
             // Filter supported triples with versionLessTriple and pass into
             // ExecutableInfo; empty if non matching triples found.
             try entry.value.variants.map{
-                ExecutableInfo(name: entry.key, executablePath: try AbsolutePath(validating: $0.path, relativeTo: self.artifactPath), supportedTriples: $0.supportedTriples.filter({$0 == versionLessTriple}))
+                return ExecutableInfo(name: entry.key, executablePath: try AbsolutePath(validating: $0.path, relativeTo: self.artifactPath), supportedTriples: try $0.supportedTriples.filter({try $0.withoutVersion() == versionLessTriple}))
             }
         }
     }
 }
 
-fileprivate extension Triple {
+extension Triple {
     func withoutVersion() throws -> Triple {
         if isDarwin() {
             let stringWithoutVersion = tripleString(forPlatformVersion: "")

Sources/SPMBuildCore/PluginInvocation.swift

@@ -373,7 +373,7 @@ extension PackageGraph {
                 let toolNamesToTriples = accessibleTools.reduce(into: [String: [String]](), { dict, tool in
                     switch tool {
                     case .vendedTool(let name, _, let triple):
-                        dict[name] = triple
+                        dict[name, default: []].append(contentsOf: triple)
                     default: break
                     }
                 })
@@ -533,7 +533,7 @@ public extension PluginTarget {
             if let target = executableOrBinaryTarget as? BinaryTarget {
                 // TODO: Memoize this result for the host triple
                 let execInfos = try target.parseArtifactArchives(for: hostTriple, fileSystem: fileSystem)
-                return execInfos.map{ .vendedTool(name: $0.name, path: $0.executablePath, supportedTriples: $0.supportedTriples.map{$0.tripleString}) }
+                return try execInfos.map{ .vendedTool(name: $0.name, path: $0.executablePath, supportedTriples: try $0.supportedTriples.map{ try $0.withoutVersion().tripleString }) }
             }
             // For an executable target we create a `builtTool`.
             else if executableOrBinaryTarget.type == .executable {