[CMake][Fuchsia] Drop Darwin architectures

We want to build all available ones.

Differential Revision: https://reviews.llvm.org/D122022

Author: petrhosek

clang/cmake/caches/Fuchsia-stage2.cmake

@@ -70,9 +70,6 @@ if(APPLE)
   set(LIBCXX_ENABLE_SHARED OFF CACHE BOOL "")
   set(LIBCXX_ENABLE_STATIC_ABI_LIBRARY ON CACHE BOOL "")
   set(LIBCXX_ABI_VERSION 2 CACHE STRING "")
-  set(DARWIN_ios_ARCHS arm64 CACHE STRING "")
-  set(DARWIN_iossim_ARCHS arm64 CACHE STRING "")
-  set(DARWIN_osx_ARCHS arm64;x86_64 CACHE STRING "")
 endif()
 
 if(WIN32)