Re: [PATCH] use m4_require to implement AS_REQUIRE

[Paolo Bonzini]

>>   ac_c_check_func() {
>>     if test $ac_cv...; then
>>       ...
>>     else
>>       ac_c_link_ifelse() {
>>       }
>>     fi
>>   }
>>
>> which does not work of course.
> 
> For me mere mortal, who doesn't wade in the problems you've studied in
> detail, what exactly is problematic here?

Suppose you have:

ac_c_check_func function_that_is_in_cached
... some other test that does uses AC_LINK_IFELSE ...

ac_c_link_ifelse won't be defined.