llvmPackages_15.compiler-rt: fix missing builtins

Darwin-specific builtins were present on x86-64-darwin, but not on
aarch64-darwin. This is the same issue as #186575, but while the fixes
were correctly applied to LLVM 15, we were still disabling the build of
builtins on aarch64-darwin. Likely just a confusion.

pkgs/development/compilers/llvm/15/compiler-rt/default.nix

@@ -97,8 +97,6 @@ stdenv.mkDerivation {
     substituteInPlace cmake/builtin-config-ix.cmake \
       --replace 'set(X86 i386)' 'set(X86 i386 i486 i586 i686)'
   '' + lib.optionalString stdenv.isDarwin ''
-    substituteInPlace cmake/builtin-config-ix.cmake \
-      --replace 'set(ARM64 arm64 arm64e)' 'set(ARM64)'
     substituteInPlace cmake/config-ix.cmake \
       --replace 'set(COMPILER_RT_HAS_TSAN TRUE)' 'set(COMPILER_RT_HAS_TSAN FALSE)'
   '' + lib.optionalString (useLLVM) ''