libsvgtiny: disable -Werror

glibc-2.20 includes some changes to the include/features.h file
introduced by this commit:

  https://sourceware.org/git/?p=glibc.git;a=commit;h=ade40b10ff5fa59a318cf55b9d8414b758e8df78

Those changes make libsvgtiny fail because some warnings are thrown and
the build system is using the -Werror option. We disable this to be able
to build it, or otherwise we will see errors like this one:

GPERF: src/colors.gperf
COMPILE: build-Linux-Linux-release-lib-static/src_colors.c
In file included from
/br/output/host/usr/mipsel-buildroot-linux-gnu/sysroot/usr/include/string.h:25:0,
		 from src/colors.gperf:16:
/br/output/host/usr/mipsel-buildroot-linux-gnu/sysroot/usr/include/features.h:148:3:
error: #warning "_BSD_SOURCE and _SVID_SOURCE are deprecated, use
_DEFAULT_SOURCE" [-Werror=cpp]

and this one:

In file included from src/colors.gperf:18:0:
/home/ldap/vriera/work/mips-buildroots/mips32/output/build/libsvgtiny-12121/src/svgtiny_internal.h:71:0:
error: "strndup" redefined [-Werror]

Fixes:
  http://autobuild.buildroot.net/results/3dd/3dd700405055750262738f867eb5aa08531f5781/

Signed-off-by: Vicente Olivert Riera <Vincent.Riera@imgtec.com>
Reviewed-by: Markos Chandras <Markos.Chandras@imgtec.com>
---
 package/libsvgtiny/libsvgtiny.mk |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)

Dear Vicente Olivert Riera,

On Wed, 10 Dec 2014 14:59:32 +0000, Vicente Olivert Riera wrote:
> glibc-2.20 includes some changes to the include/features.h file
> introduced by this commit:
> 
>   https://sourceware.org/git/?p=glibc.git;a=commit;h=ade40b10ff5fa59a318cf55b9d8414b758e8df78
> 
> Those changes make libsvgtiny fail because some warnings are thrown and
> the build system is using the -Werror option. We disable this to be able
> to build it, or otherwise we will see errors like this one:
> 
> GPERF: src/colors.gperf
> COMPILE: build-Linux-Linux-release-lib-static/src_colors.c
> In file included from
> /br/output/host/usr/mipsel-buildroot-linux-gnu/sysroot/usr/include/string.h:25:0,
> 		 from src/colors.gperf:16:
> /br/output/host/usr/mipsel-buildroot-linux-gnu/sysroot/usr/include/features.h:148:3:
> error: #warning "_BSD_SOURCE and _SVID_SOURCE are deprecated, use
> _DEFAULT_SOURCE" [-Werror=cpp]
> 
> and this one:
> 
> In file included from src/colors.gperf:18:0:
> /home/ldap/vriera/work/mips-buildroots/mips32/output/build/libsvgtiny-12121/src/svgtiny_internal.h:71:0:
> error: "strndup" redefined [-Werror]
> 
> Fixes:
>   http://autobuild.buildroot.net/results/3dd/3dd700405055750262738f867eb5aa08531f5781/
> 
> Signed-off-by: Vicente Olivert Riera <Vincent.Riera@imgtec.com>
> Reviewed-by: Markos Chandras <Markos.Chandras@imgtec.com>

If you have some time, it would be good to report upstream that they
shouldn't use -Werror, and to fix the warnings themselves.

Thanks a lot!

Thomas

Dear Vicente Olivert Riera,

On Wed, 10 Dec 2014 14:59:32 +0000, Vicente Olivert Riera wrote:

> +define LIBSVGTINY_DISABLE_WERROR
> +	$(SED) 's/-Werror//' $(@D)/Makefile
> +endef
> +LIBSVGTINY_POST_CONFIGURE_HOOKS += LIBSVGTINY_DISABLE_WERROR

As discussed on IRC, I would prefer this to be done using a patch
rather than a $(SED) command, for several reasons:

 * A $(SED) command that replaces some random string can start breaking
   when we bump the libsvgtiny Makefile, as it might start replacing
   other things than what was intended.

 * We will never notice when the $(SED) command will no longer be
   useful. With a patch, when we'll bump libsvgtiny, we'll get some
   conflict when re-applying the patch on the new version of
   libsvgtiny, and so we'll see if we can drop the patch, or if we need
   to re-adjust the patch.

Care to resend as a patch instead?

Thanks!

Thomas