Re: Autoconf protype breaks GCC builtin inlining

[Paul Eggert]

On 01/24/2018 01:36 PM, Ferenc Wágner wrote:
> in the actual code where math.h is #included, the
> above warning does not happen, ceil is inlined and I unnecessarily link
> with -lm.  How could I overcome this?

I don't see an easy workaround at the autoconf level. The compiler makes 
the decision whether to inline, and this decision can depend on a lot of 
things. The compiler's decision for the Autoconf-generated snippet might 
disagree with the compiler's decision in the rest of your code, so this 
is not something that one can safely test for at 'configure'-time.

To some extent you've lucked out because for you 'configure' tells 
'make' to use -lm, so the worst that can happen for you is linking a 
library unnecessarily. If it made the opposite mistake, the program 
wouldn't link at all.