SwiftBuild Integration: Enable some sanitizers

Update the SwiftPM's SwiftBuild integration to support enabling
`address`, `thread` and `undefined` sanitizers while erroring out on
the `scudo` and `fuzzer`.

Depends on: swiftlang/swift-build#926

Author: bkhouri

Sources/SwiftBuildSupport/SwiftBuildSystem.swift

@@ -885,6 +885,20 @@ public final class SwiftBuildSystem: SPMBuildCore.BuildSystem {
             settings["SWIFT_EXEC"] = buildParameters.toolchain.swiftCompilerPath.pathString
         }
 
+        for sanitizer in buildParameters.sanitizers.sanitizers {
+            self.observabilityScope.emit(debug:"Enabling \(sanitizer) sanitizer")
+            switch sanitizer {
+                case .address:
+                    settings["ENABLE_ADDRESS_SANITIZER"] = "YES"
+                case .thread:
+                    settings["ENABLE_THREAD_SANITIZER"] = "YES"
+                case .undefined:
+                    settings["ENABLE_UNDEFINED_BEHAVIOR_SANITIZER"] = "YES"
+                case .fuzzer, .scudo:
+                    throw StringError("\(sanitizer) is not currently supported with this build system.")
+            }
+        }
+
         // FIXME: workaround for old Xcode installations such as what is in CI
         settings["LM_SKIP_METADATA_EXTRACTION"] = "YES"
         if let symbolGraphOptions {
@@ -1223,13 +1237,13 @@ fileprivate extension SwiftBuild.SwiftBuildMessage.DiagnosticInfo.Location {
             case .none:
                 return path
             }
-        
+
         case .buildSettings(let names):
             return names.joined(separator: ", ")
-        
+
         case .buildFiles(let buildFiles, let targetGUID):
             return "\(targetGUID): " + buildFiles.map { String(describing: $0) }.joined(separator: ", ")
-            
+
         case .unknown:
             return nil
         }