> On Tue, Jun 2, 2026, at 3:04 PM, Jose E. Marchesi wrote:
>> Hi Pietro.
>>
>>> if test x$may_have_cet = xyes; then
>>> if test x$cross_compiling = xno; then
>>> - AC_TRY_RUN([
>>> + AC_RUN_IFELSE([AC_LANG_SOURCE([[
>>> int
>>> main ()
>>> {
>>> asm ("endbr32");
>>> return 0;
>>> }
>>> - ],
>>> + ]])],
>>> [have_multi_byte_nop=yes],
>>> - [have_multi_byte_nop=no])
>>> + [have_multi_byte_nop=no],
>>> + [AC_MSG_FAILURE(cannot run test program while cross compiling)])
>>> have_cet=no
>>> if test x$have_multi_byte_nop = xyes; then
>>
>> According to the AU_DEFUN in autoconf 2.69:
>>
>>
>> # AC_TRY_RUN(PROGRAM,
>> # [ACTION-IF-TRUE], [ACTION-IF-FALSE],
>> # [ACTION-IF-CROSS-COMPILING = RUNTIME-ERROR])
>> # -------------------------------------------------------
>> AU_DEFUN([AC_TRY_RUN],
>> [AC_RUN_IFELSE([AC_LANG_SOURCE([[$1]])], [$2], [$3], [$4])])
>>
>> And AC_RUN_IFELSE provides a default $4 argument with:
>>
>> [m4_default([$4],
>> [AC_MSG_FAILURE([cannot run test program while cross
>> compiling])])]
>>
>> See autoconf/lib/autoconf/general.m4. Is it necessary to provide an
>> explicit argument here?
>
> It isn't necessary. As you noted, I'm using the same default as
> autoconf and there's no difference in the generated files wheter the
> argument is present. But autoconf prints a warning message when
> AC_RUN_IFELSE has no action-if-cross-compiling argument. And getting
> rid of the warnings is the main goal here.
Yeah I see...
AC_DEFUN([AC_RUN_IFELSE],
[AC_LANG_COMPILER_REQUIRE()dnl
m4_ifval([$4], [],
[m4_warn([cross],
[$0 called without default to allow cross compiling])])dnl
AS_IF([test "$cross_compiling" = yes],
[m4_default([$4],
[AC_MSG_FAILURE([cannot run test program while cross compiling])])],
[_AC_RUN_IFELSE($@)])
])
That's annoying.
