CMake: Define DARWIN_LIBMALLOC

`SWIFT_STDLIB_HAS_MALLOC_TYPE` is defined in terms of
`SWIFT_STDLIB_HAS_DARWIN_LIBMALLOC` in `include/swift/Runtime/Config.h`.
Apple platforms generally have the Darwin libmalloc, so it should be a
safe bet to define it this way. Unfortunately, a lot of things include
the Config.h file, transitively or otherwise, so figuring out exactly
which libraries should have this defined vs ones that should not is
rather tricky, so for now, I've defined it globally.

Author: etcwilde

Runtimes/Core/CMakeLists.txt

@@ -92,7 +92,6 @@ defaulted_option(SwiftCore_ENABLE_RUNTIME_FUNCTION_COUNTERS "Enable runtime func
 defaulted_option(SwiftCore_ENABLE_STDIN "Enable functions that use stdin support")
 defaulted_option(SwiftCore_ENABLE_ENVIRONMENT "Enable environment variable support")
 defaulted_option(SwiftCore_ENABLE_OVERRIDABLE_RETAIN_RELEASE "Enable override hooks for retain/release")
-defaulted_option(SwiftCore_ENABLE_MALLOC_TYPE "Enable malloc type information")
 defaulted_option(SwiftCore_ENABLE_RUNTIME_OS_VERSIONING "Enable runtime OS version detection")
 defaulted_option(SwiftCore_ENABLE_STATIC_PRINT "Disable full print")
 defaulted_option(SwiftCore_ENABLE_COMPACT_ABSOLUTE_FUNCTION_POINTERS "Resolve absolute function pointer as identity")
@@ -102,6 +101,7 @@ option(SwiftCore_ENABLE_UNICODE_DATA "Include unicode data in Swift runtimes" ON
 option(SwiftCore_ENABLE_SHORT_MANGLING_LOOKUPS "Build with fast-path context descriptor lookups based on well-known short manglings." ON)
 option(SwiftCore_ENABLE_FILESYSTEM_SUPPORT "Build for systems that have a filesystem" ON)
 option(SwiftCore_ENABLE_OS_TRACE_LAZY_INIT "Use os_trace call to check if lazy init has been completed before making os_signpost calls." ${SwiftCore_HAS_OS_TRACE})
+option(SwiftCore_HAS_DARWIN_LIBMALLOC "Use Darwin malloc features" ${APPLE})
 
 defaulted_option(SwiftCore_ENABLE_BACKTRACING "Enable backtracing runtime support")
 defaulted_set(SwiftCore_BACKTRACER_PATH STRING "Set a fixed path to the Swift backtracer")
@@ -135,6 +135,7 @@ add_compile_definitions(
   $<$<BOOL:${SwiftCore_ENABLE_UNICODE_DATA}>:-DSWIFT_STDLIB_ENABLE_UNICODE_DATA> # Stubs
   $<$<BOOL:${SwiftCore_ENABLE_ENVIRONMENT}>:-DSWIFT_STDLIB_HAS_ENVIRON> # Concurrency, runtime, shims, platform overlay
   $<$<BOOL:${SwiftCore_ENABLE_BACKDEPLOYMENT_SUPPORT}>:-DSWIFT_STDLIB_SUPPORT_BACK_DEPLOYMENT> # Concurrency, Compatibility override, magic symbols
+  $<$<BOOL:${SwiftCore_HAS_DARWIN_LIBMALLOC}>:-DSWIFT_STDLIB_HAS_DARWIN_LIBMALLOC> # Anything that includes include/swift/Runtime/Config.h
   $<$<COMPILE_LANGUAGE:C,CXX>:-DSWIFT_THREADING_${SwiftCore_THREADING_PACKAGE}>
   $<$<COMPILE_LANGUAGE:C,CXX>:-DSWIFT_RUNTIME_ENABLE_LEAK_CHECKER=$<BOOL:${SwiftCore_ENABLE_RUNTIME_LEAK_CHECKER}>>
   $<$<COMPILE_LANGUAGE:C,CXX>:-DSWIFT_RUNTIME_CLOBBER_FREED_OBJECTS=$<BOOL:${SwiftCore_ENABLE_CLOBBER_FREED_OBJECTS}>>)

Runtimes/Core/runtime/CMakeLists.txt

@@ -90,7 +90,6 @@ target_compile_definitions(swiftRuntime
     $<$<BOOL:${BUILD_SHARED_LIBS}>:-DswiftCore_EXPORTS>
     $<$<BOOL:${SwiftCore_ENABLE_BACKTRACING}>:-DSWIFT_ENABLE_BACKTRACING>
     $<$<BOOL:${SwiftCore_ENABLE_OVERRIDABLE_RETAIN_RELEASE}>:-DSWIFT_STDLIB_OVERRIDABLE_RETAIN_RELEASE>
-    $<$<BOOL:${SwiftCore_ENABLE_MALLOC_TYPE}>:-DSWIFT_STDLIB_HAS_MALLOC_TYPE>
     $<$<BOOL:${SwiftCore_BACKTRACER_PATH}>:-DSWIFT_RUNTIME_FIXED_BACKTRACER_PATH="${SwiftCore_BACKTRACER_PATH}">
     $<$<BOOL:${SwiftCore_ENABLE_STDLIB_TRACING}>:-DSWIFT_STDLIB_TRACING>
     $<$<BOOL:${SwiftCore_ENABLE_SHORT_MANGLING_LOOKUPS}>:-DSWIFT_STDLIB_SHORT_MANGLING_LOOKUPS>