Adding ELF swiftrt for BSD and Android

BSD and Android also need to build swiftrt.o so adding it to the
default settings.

Author: etcwilde

Runtimes/Core/cmake/modules/DefaultSettings.cmake

@@ -24,7 +24,7 @@ if(APPLE)
   set(SwiftCore_ENABLE_REFLECTION_default ON)
 elseif(CMAKE_SYSTEM_NAME STREQUAL "WASM")
   set(SwiftCore_OBJECT_FORMAT_default "elf")
-elseif(LINUX)
+elseif(LINUX OR ANDROID OR BSD)
   set(SwiftCore_OBJECT_FORMAT_default "elf")
 elseif(WIN32)
   set(SwiftCore_OBJECT_FORMAT_default "coff")