RFR: 8366777: Build fails unknown pseudo-op with old AS on linux-aarch64 [v6]

[SendaoYan]

On Fri, 5 Sep 2025 12:58:51 GMT, Erik Joelsson <erikj at openjdk.org> wrote:

>> SendaoYan has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Use UTIL_ARG_ENABLE instead of AC_ARG_ENABLE
>
> make/autoconf/flags-cflags.m4 line 950:
> 
>> 948:       # check the compiler and binutils support sve or not
>> 949:       AC_MSG_CHECKING([if Arm SVE ACLE is supported])
>> 950:       AC_COMPILE_IFELSE([AC_LANG_PROGRAM(
> 
> Now that I started looking closer at this, I realize that we are inside a macro that gets called for both the BUILD and TARGET compiler (note the $2 prefix on several variables). For a call to `AC_COMPILER_IFELSE` to work correctly in that context, you need to temporarily change `CC` and `CFLAGS` to the correct compiler and flags setup. See the definition of `FLAGS_C_COMPILER_CHECK_ARGUMENTS` in flags.m4 to see how that is done.

Thanks for the review and suggestion. Fixed.

-------------

PR Review Comment: https://git.openjdk.org/jdk/pull/27073#discussion_r2336117442