FTBFS with gcc-10 (or -fno-common)

[OdyX]

It has been reported in Debian that sdl-kitchensink fails to build from source with gcc-10, see https://bugs.debian.org/957784

/usr/bin/ld: CMakeFiles/SDL_kitchensink.dir/src/internal/subtitle/renderers/kitsubass.c.o:./obj-x86_64-linux-gnu/./include/kitchensink/internal/libass.h:53: multiple definition of `ass_process_chunk'; CMakeFiles/SDL_kitchensink.dir/src/internal/audio/kitaudio.c.o:./obj-x86_64-linux-gnu/./include/kitchensink/internal/libass.h:53: first defined here
…

As documented here https://gcc.gnu.org/gcc-10/porting_to.html;

A common mistake in C is omitting extern when declaring a global variable in a header file. If the header is included by several files it results in multiple definitions of the same variable. In previous GCC versions this error is ignored. GCC 10 defaults to -fno-common, which means a linker error will now be reported.

Indeed, I can confirm that passing -fcommon to gcc will let the build pass, but this is just a temporary workaround I would say.

Platform

• OS: Debian unstable/sid as of 2020-07-23, with GCC-10
• SDL version 2.0.12+dfsg1-1
• FFMPEG version: 7:4.3-3+b1
• SDL_Kitchensink version : 1.0.8

[katajakasa]

Thanks for reporting this! Unfortunately, the dynamic linking of libass is a bit of a kludge, and I don't usually test it. That's why I had missed this. Added a quick fix on the PR, please test it out if you have the time. I will probably poke at it more a bit later, and then merge and roll a release if there are no issues.

[katajakasa]

Fixed and released in v1.0.9