Re: [PATCH] objtool: fix build with future Make

[Masahiro Yamada]

2018-03-26 7:32 GMT+09:00 Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>:
> I tried building using a freshly built Make (4.2.1-69-g8a731d1), but the
> objtool build broke with
>
> orc_dump.c: In function âorc_dumpâ:
> orc_dump.c:106:2: error: âelf_getshnumâ is deprecated [-Werror=deprecated-declarations]
>   if (elf_getshdrnum(elf, &nr_sections)) {
>
> Turns out that with that new Make, the backslash was not removed, so cpp
> didn't see a #include directive, grep found nothing, and
> -DLIBELF_USE_DEPRECATED was wrongly put in CFLAGS.
>
> Now, that new Make behaviour is documented in their NEWS file:
>
>   * WARNING: Backward-incompatibility!
>     Number signs (#) appearing inside a macro reference or function invocation
>     no longer introduce comments and should not be escaped with backslashes:
>     thus a call such as:
>       foo := $(shell echo '#')
>     is legal.  Previously the number sign needed to be escaped, for example:
>       foo := $(shell echo '\#')
>     Now this latter will resolve to "\#".  If you want to write makefiles
>     portable to both versions, assign the number sign to a variable:
>       C := \#
>       foo := $(shell echo '$C')
>     This was claimed to be fixed in 3.81, but wasn't, for some reason.
>     To detect this change search for 'nocomment' in the .FEATURES variable.
>
> There are likely other places in the tree that will need fixing, so
> cc-ing Kbuild, but with this at least a x86-64 defconfig builds.
>
> Signed-off-by: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
> ---

Reviewed-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>




-- 
Best Regards
Masahiro Yamada