Properly compute resource folder when linking statically

- deduplicate the logic to compute the resource folder
- install headers and module files in shared and static resource folders
- forward -static flag when calling swiftc with -print-target-info

include/swift/Frontend/Frontend.h

@@ -128,7 +128,8 @@ public:
   bool parseArgs(ArrayRef<const char *> Args, DiagnosticEngine &Diags,
                  SmallVectorImpl<std::unique_ptr<llvm::MemoryBuffer>>
                      *ConfigurationFileBuffers = nullptr,
-                 StringRef workingDirectory = {});
+                 StringRef workingDirectory = {},
+                 StringRef mainExecutablePath = {});
 
   /// Sets specific options based on the given serialized Swift binary data.
   ///
@@ -213,8 +214,11 @@ public:
   /// Computes the runtime resource path relative to the given Swift
   /// executable.
   static void computeRuntimeResourcePathFromExecutablePath(
-      StringRef mainExecutablePath,
-      llvm::SmallString<128> &runtimeResourcePath);
+      StringRef mainExecutablePath, bool shared,
+      llvm::SmallVectorImpl<char> &runtimeResourcePath);
+
+  /// Appends `lib/swift[_static]` to the given path
+  static void appendSwiftLibDir(llvm::SmallVectorImpl<char> &path, bool shared);
 
   void setSDKPath(const std::string &Path);