[AArch64] Fix COMPILER_RT_HAS_AUXV for builtins. (#84816)

COMPILER_RT_HAS_AUXV is used now in builtins so the test need to be in
the builtin-config-ix.cmake too.

Author: DanielKristofKiss

compiler-rt/cmake/builtin-config-ix.cmake

@@ -1,4 +1,5 @@
 include(BuiltinTests)
+include(CheckIncludeFiles)
 include(CheckCSourceCompiles)
 
 # Make all the tests only check the compiler
@@ -43,6 +44,8 @@ void foo(void)  __arm_streaming_compatible {
 }
 ")
 
+check_include_files("sys/auxv.h"    COMPILER_RT_HAS_AUXV)
+
 if(ANDROID)
   set(OS_NAME "Android")
 else()