[lldb] Simplify CMake logic with LLVM's append_if function

Use the append_if CMake function from HandleLLVMOptions. Since we
include this file in LLDBStandalone it should work in both for in-tree
and out-of-tree builds.

diff --git a/lldb/cmake/modules/LLDBConfig.cmake b/lldb/cmake/modules/LLDBConfig.cmake
index b0c139e..b149836 100644 (file)
--- a/lldb/cmake/modules/LLDBConfig.cmake
+++ b/lldb/cmake/modules/LLDBConfig.cmake
@@ -159,36 +159,21 @@ endif ()
 include_directories("${CMAKE_CURRENT_BINARY_DIR}/../clang/include")
 
 # Disable GCC warnings
-check_cxx_compiler_flag("-Wno-deprecated-declarations"
-                        CXX_SUPPORTS_NO_DEPRECATED_DECLARATIONS)
-if (CXX_SUPPORTS_NO_DEPRECATED_DECLARATIONS)
-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-deprecated-declarations")
-endif ()
+check_cxx_compiler_flag("-Wno-deprecated-declarations" CXX_SUPPORTS_NO_DEPRECATED_DECLARATIONS)
+append_if(CXX_SUPPORTS_NO_DEPRECATED_DECLARATIONS "-Wno-deprecated-declarations" CMAKE_CXX_FLAGS)
 
-check_cxx_compiler_flag("-Wno-unknown-pragmas"
-                        CXX_SUPPORTS_NO_UNKNOWN_PRAGMAS)
-if (CXX_SUPPORTS_NO_UNKNOWN_PRAGMAS)
-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-unknown-pragmas")
-endif ()
+check_cxx_compiler_flag("-Wno-unknown-pragmas" CXX_SUPPORTS_NO_UNKNOWN_PRAGMAS)
+append_if(CXX_SUPPORTS_NO_UNKNOWN_PRAGMAS "-Wno-unknown-pragmas" CMAKE_CXX_FLAGS)
 
-check_cxx_compiler_flag("-Wno-strict-aliasing"
-                        CXX_SUPPORTS_NO_STRICT_ALIASING)
-if (CXX_SUPPORTS_NO_STRICT_ALIASING)
-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-strict-aliasing")
-endif ()
+check_cxx_compiler_flag("-Wno-strict-aliasing" CXX_SUPPORTS_NO_STRICT_ALIASING)
+append_if(CXX_SUPPORTS_NO_STRICT_ALIASING "-Wno-strict-aliasing" CMAKE_CXX_FLAGS)
 
 # Disable Clang warnings
-check_cxx_compiler_flag("-Wno-deprecated-register"
-                        CXX_SUPPORTS_NO_DEPRECATED_REGISTER)
-if (CXX_SUPPORTS_NO_DEPRECATED_REGISTER)
-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-deprecated-register")
-endif ()
+check_cxx_compiler_flag("-Wno-deprecated-register" CXX_SUPPORTS_NO_DEPRECATED_REGISTER)
+append_if(CXX_SUPPORTS_NO_DEPRECATED_REGISTER "-Wno-deprecated-register" CMAKE_CXX_FLAGS)
 
-check_cxx_compiler_flag("-Wno-vla-extension"
-                        CXX_SUPPORTS_NO_VLA_EXTENSION)
-if (CXX_SUPPORTS_NO_VLA_EXTENSION)
-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-vla-extension")
-endif ()
+check_cxx_compiler_flag("-Wno-vla-extension" CXX_SUPPORTS_NO_VLA_EXTENSION)
+append_if(CXX_SUPPORTS_NO_VLA_EXTENSION "-Wno-vla-extension" CMAKE_CXX_FLAGS)
 
 # Disable MSVC warnings
 if( MSVC )