[SwiftCompilerSources] Add missing import

Author: xymus

SwiftCompilerSources/Sources/Basic/SourceLoc.swift

@@ -10,6 +10,8 @@
 //
 //===----------------------------------------------------------------------===//
 
+import ASTBridging
+
 public struct SourceLoc {
   /// Points into a source file.
   let locationInFile: UnsafePointer<UInt8>