Update master branch for Xcode 12 beta

README.md

@@ -97,7 +97,7 @@ Please make sure you use Python 2.x. Python 3.x is not supported currently.
 
 #### macOS
 
-To build for macOS, you need [Xcode 11.4](https://developer.apple.com/xcode/resources/).
+To build for macOS, you need [Xcode 12 beta](https://developer.apple.com/xcode/resources/).
 The required version of Xcode changes frequently, and is often a beta release.
 Check this document or the host information on <https://ci.swift.org> for the
 current required version.

benchmark/cmake/modules/AddSwiftBenchmarkSuite.cmake

@@ -660,8 +660,11 @@ function (swift_benchmark_compile_archopts)
           "-m${triple_platform}-version-min=${ver}"
           "-lobjc"
           "-L${SWIFT_LIBRARY_PATH}/${BENCH_COMPILE_ARCHOPTS_PLATFORM}"
+          "-L${sdk}/usr/lib/swift"
           "-Xlinker" "-rpath"
           "-Xlinker" "${SWIFT_LINK_RPATH}"
+          "-Xlinker" "-rpath"
+          "-Xlinker" "/usr/lib/swift"
           ${bench_library_objects}
           ${bench_driver_objects}
           ${ld64_add_ast_path_opts}

stdlib/cmake/modules/AddSwiftStdlib.cmake

@@ -1120,6 +1120,8 @@ function(_add_swift_target_library_single target name)
       list(APPEND library_search_directories "$ENV{SDKROOT}/usr/lib/swift")
   endif()
 
+  list(APPEND library_search_directories "${SWIFT_SDK_${sdk}_ARCH_${arch}_PATH}/usr/lib/swift")
+
   # Add variant-specific flags.
   if(SWIFTLIB_SINGLE_TARGET_LIBRARY)
     set(build_type "${SWIFT_STDLIB_BUILD_TYPE}")