[Arm-toolchain] [ATfE] Disable libxml2 in ATfE (#169)

- libxml2 is an external dependency used by lld's coff port lld-link to
merge XML manifest files
- We don't need this dependency for ATfE

Author: HugoSilvaSantos

arm-software/embedded/CMakeLists.txt

@@ -240,6 +240,7 @@ set(LLVM_APPEND_VC_REV OFF CACHE BOOL "")
 set(LLVM_ENABLE_TERMINFO OFF CACHE BOOL "")
 set(LLVM_ENABLE_ZLIB OFF CACHE BOOL "")
 set(LLVM_ENABLE_ZSTD OFF CACHE BOOL "")
+set(LLVM_ENABLE_LIBXML2 OFF CACHE BOOL "")
 set(CLANG_DEFAULT_LINKER lld CACHE STRING "")
 
 # Default to a release build