Cherry-pick upstream autolinking changes

Cherry-picking upstream swiftlang#3052

Author: MaxDesiatov

Sources/Foundation/CMakeLists.txt

@@ -166,18 +166,28 @@ set_target_properties(Foundation PROPERTIES
   INTERFACE_INCLUDE_DIRECTORIES ${CMAKE_BINARY_DIR}/swift)
 
 if(NOT BUILD_SHARED_LIBS)
-  add_dependencies(Foundation CoreFoundation uuid)
-  target_compile_options(Foundation
-    PRIVATE
-      "SHELL:-Xfrontend -public-autolink-library -Xfrontend icui18n
-             -Xfrontend -public-autolink-library -Xfrontend BlocksRuntime")
+   # ICU_I18N_LIBRARY is set by find_package(ICU) in the top level CMakeLists.txt
+   # It's an absolute path to the found library file
+   get_target_property(icui18n_path ICU::i18n IMPORTED_LOCATION)
+   get_filename_component(icu_i18n_basename "${icui18n_path}" NAME_WE)
+   get_filename_component(icu_i18n_dir "${icui18n_path}" DIRECTORY)
+   string(REPLACE "lib" "" icu_i18n_basename "${icu_i18n_basename}")
 
-  # Merge private dependencies into single static objects archive
-  set_property(TARGET Foundation PROPERTY STATIC_LIBRARY_OPTIONS
-    $<TARGET_OBJECTS:CoreFoundation>
-    $<TARGET_OBJECTS:uuid>
-    $<TARGET_OBJECTS:BlocksRuntime>)
-endif()
+   target_compile_options(Foundation
+     PRIVATE
+       "SHELL:-Xfrontend -public-autolink-library -Xfrontend ${icu_i18n_basename}
+              -Xfrontend -public-autolink-library -Xfrontend BlocksRuntime")
+   # ICU libraries are linked by absolute library path in this project,
+   # but -public-autolink-library forces to resolve library path by
+   # library search path given by -L, so add a directory of icui18n
+   # in the search path
+   target_link_directories(Foundation PUBLIC "${icu_i18n_dir}")
+
+   # Merge private dependencies into single static objects archive
+   set_property(TARGET Foundation PROPERTY STATIC_LIBRARY_OPTIONS
+     $<TARGET_OBJECTS:CoreFoundation>
+     $<TARGET_OBJECTS:uuid>)
+ endif()
 
 if(CMAKE_SYSTEM_NAME STREQUAL Windows)
   # NOTE: workaround for CMake which doesn't link in OBJECT libraries properly