Re: [ANN] m4-1.4.17 released [stable]

[Eric Blake]

On 09/23/2013 09:32 AM, Paul Eggert wrote:
> Eric Blake wrote:
>> is this
>> something where you can tackle the gnulib patch faster than I can?
> 
> I can test something easily, yes, but I'm not sure what
> direction you're headed here.

Basically, gl_WARN_ADD in gnulib/m4/warnings.m4 is trying to probe
whether adding -fdiagnostics-show-option to CFLAGS appears to be
accepted by the compiler (no change in exit status); and if so, turns it
on; but turning it on is wrong for the Sun compiler.  Either
gl_UNKNOWN_WARNINGS_ARE_ERRORS should add a clause that turns on the
ability for Sun to force unknown CFLAGS to be an error, or we need to
patch gl_COMPILER_OPTION_IF to scan for the stderr message produced by
Sun when it ignores an unknown option and treat that as
option-not-supported, instead of the current case of adding it to CFLAGS
only to cause link failures later when the linker chokes on an unknown
-f option.

Having typed that, maybe it's sufficient to change gl_COMPILER_OPTION_IF
to use AC_LINK_IFELSE instead of AC_COMPILE_IFELSE?

Side note: -fdiagnostics-show-option is very useful for gcc; perhaps we
should tweak m4/manywarnings.m4 to add it to the set of warnings probed
by default when gcc warnings are enabled, instead of making packages
like m4 check for it themselves.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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