[FFmpeg-devel] [PATCH 3/3] configure: Remove -Wredundant-decls on OS/2 to suppress noise.

[Dmitriy Kuminov]

On 2016-04-21 06:46:38 +0000, Reimar Döffinger said:

> Have something that results in adding -I/usr/include to the compile 
> options or to C_INCLUDE_PATH? Probably your compiler is misconfigured 
> to not consider that a system include path.
> Adding -isystem /usr/include should fix it.

I finally had some time to research. No, our compiler (at least the RPM 
releases from BWW) is not misconfigured, /@unixroot/usr/include is the 
system include path and a simple `gcc -Zomf -Wredundant-decls -c 
hello.c` works well. However, when building FFmpeg stuff, 
-I/@unxroot/usr/include indeed ends up in CFLAGS multiple times and all 
these come from .pc files (namely, fontconfig.pc and vpx.pc). And from 
what I see in the sources, -I${includedir} a very common thing which is 
often used in Cflags: in .pc.in, including fontconfig.pc.in (and 
{includedir} is normally /usr/include or such). So all other platforms 
should be suffering from -Wredundant-decls as well (unless their libc 
headers are very clean and don't contain duplicate decls).

So unless I miss something else, we should still apply this patch (as 
fixing OS/2 libc headers won't happen any time soon).

-- 
Kind regards,
Dmitriy Kuminov
CPO of bww bitwise works GmbH