cmake: HAVE_GCC_PREFERRED_STACK_BOUNDARY is not used anymore

CMakeLists.txt

@@ -612,12 +612,6 @@ if(USE_GCC OR USE_CLANG)
     endif()
   endif()
 
-  cmake_push_check_state()
-  set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -mpreferred-stack-boundary=2")
-  check_c_source_compiles("int x = 0; int main(int argc, char **argv) { return 0; }"
-    HAVE_GCC_PREFERRED_STACK_BOUNDARY)
-  cmake_pop_check_state()
-
   cmake_push_check_state()
   set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -fvisibility=hidden -Werror")
   check_c_source_compiles("