Re: Add clang++ to AC_PROG_CXX

[Václav Haisman]

On 16 March 2016 at 16:30, Earnie <address@hidden> wrote:
> (...)
> Rather than adding to this list of tools how about a configure.ac macro.
>  Something named AC_REQUIRE_TOOL sounds correct and then AC_CHECK_TOOLS
> also checks (or maybe an option to only check) the required tool.
>
> The problem I find with the list of defaults is that it can grow and the
> more in the default list the longer the configure script will take.  If
> I have a C package then I don't want to test for anything but a C
> compiler.

But Clang is a C compiler and you are asking for one by saying
AC_PROG_CC in your configure.ac. If you are asking for a C compiler
and your environment does not have the usual cc link to some compiler,
it makes sense to look for Clang as well as any other viable compiler.
If your environment either has GCC or the cc link then you will not be
wasting any time since the checking will stop as soon as if finds one,
AFAIK.

> I don't care about any of the others and testing for them
> slows down the build process for my package.

It slows down anything only if you do not have any other viable C
compiler than Clang and even then by IMHO tiny amount.

>
> Yes I know I can set CC to be specific about which one but the users of
> the package may not have that set or may have something else entirely
> set.  My opinion is that the package maintainers need to be specific to
> the tools required and punish them by not choosing any if none is set.
> As a package maintainer I should also be able to set an option to ignore
> the environment variables for these checks since the package may be
> dependent on a specific named tool.

-- 
VH