[Clang][CMake] use CMakePushCheckState (#138783)

The previous approach of using list(REMOVE ...) would remove *all*
occurences of the given item, not just the one appended above.

Author: jeremyd2019

clang/CMakeLists.txt

@@ -183,18 +183,17 @@ check_include_file(sys/resource.h CLANG_HAVE_RLIMITS)
 # This check requires _GNU_SOURCE on linux
 check_include_file(dlfcn.h CLANG_HAVE_DLFCN_H)
 if( CLANG_HAVE_DLFCN_H )
+  include(CMakePushCheckState)
   include(CheckLibraryExists)
   include(CheckSymbolExists)
   check_library_exists(dl dlopen "" HAVE_LIBDL)
+  cmake_push_check_state()
   if( HAVE_LIBDL )
     list(APPEND CMAKE_REQUIRED_LIBRARIES dl)
   endif()
   list(APPEND CMAKE_REQUIRED_DEFINITIONS -D_GNU_SOURCE)
   check_symbol_exists(dladdr dlfcn.h CLANG_HAVE_DLADDR)
-  list(REMOVE_ITEM CMAKE_REQUIRED_DEFINITIONS -D_GNU_SOURCE)
-  if( HAVE_LIBDL )
-    list(REMOVE_ITEM CMAKE_REQUIRED_LIBRARIES dl)
-  endif()
+  cmake_pop_check_state()
 endif()
 
 set(CLANG_RESOURCE_DIR "" CACHE STRING