CMake: SwiftCore: Add Locale macro

Add locale support to new build system. The locale support depends on
finding the `clocale` C++ header.

Author: etcwilde

Runtimes/Core/CMakeLists.txt

@@ -62,6 +62,7 @@ set(SwiftCore_VENDOR_MODULE_DIR "${SwiftCore_CMAKE_MODULES_DIR}/vendor"
 
 include(GNUInstallDirs)
 include(CheckSymbolExists)
+include(CheckIncludeFileCXX)
 include(AvailabilityMacros)
 include(CompilerSettings)
 include(DefaultSettings)
@@ -73,6 +74,8 @@ include(Plist)
 check_symbol_exists("dladdr" "dlfcn.h" SwiftCore_HAS_DLADDR)
 check_symbol_exists("dlsym" "dlfcn.h" SwiftCore_HAS_DLSYM)
 
+check_include_file_cxx("clocale" SwiftCore_HAS_LOCALE)
+
 include("${SwiftCore_VENDOR_MODULE_DIR}/Settings.cmake" OPTIONAL)
 
 defaulted_option(SwiftCore_ENABLE_LIBRARY_EVOLUTION "Generate ABI resilient runtime libraries")

Runtimes/Core/stubs/CMakeLists.txt

@@ -28,7 +28,8 @@ endif()
 
 target_compile_definitions(swiftStdlibStubs PRIVATE
   $<$<BOOL:${BUILD_SHARED_LIBS}>:-DswiftCore_EXPORTS>
-  $<$<BOOL:${SwiftCore_ENABLE_UNICODE_DATA}>:-DSWIFT_STDLIB_ENABLE_UNICODE_DATA>)
+  $<$<BOOL:${SwiftCore_ENABLE_UNICODE_DATA}>:-DSWIFT_STDLIB_ENABLE_UNICODE_DATA>
+  $<$<BOOL:${SwiftCore_HAS_LOCALE}>:-DSWIFT_STDLIB_HAS_LOCALE>)
 
 target_link_libraries(swiftStdlibStubs PRIVATE
   swiftShims)