Set llvm_host_triple for cross-compiling macOS (#1004)

Since the build artifact for the cross-compiled arm build should run on an arm host, set the host variable instead of the default target triple variable

Author: Ninja3047

ports/llvm-15/portfile.cmake

@@ -294,9 +294,9 @@ set(LLVM_LINK_JOBS 2)
 
 # Cross compilation for M1
 if (VCPKG_TARGET_IS_OSX)
-    set(LLVM_DEFAULT_TARGET_TRIPLE "${VCPKG_OSX_ARCHITECTURES}-apple-darwin")
-    list(APPEND OPTIONS "-DLLVM_DEFAULT_TARGET_TRIPLE=${LLVM_DEFAULT_TARGET_TRIPLE}")
-    message(STATUS "Default target triple ${LLVM_DEFAULT_TARGET_TRIPLE}")
+    set(LLVM_HOST_TRIPLE "${VCPKG_OSX_ARCHITECTURES}-apple-darwin")
+    list(APPEND OPTIONS "-DLLVM_HOST_TRIPLE=${LLVM_HOST_TRIPLE}")
+    message(STATUS "Default host triple ${LLVM_HOST_TRIPLE}")
 endif()
 
 if (VCPKG_TARGET_ARCHITECTURE STREQUAL "arm64")