Bug#812695: pygame-sdl2: FTBFS: format not a string literal and no format arguments

[Aaron M. Ucko]

Source: pygame-sdl2
Version: 6.99.8-1
Severity: serious
Justification: fails to build from source

Builds of pygame-sdl2 with modern hardening flags have been failing:

gen/pygame_sdl2.error.c: In function ‘__pyx_pf_11pygame_sdl2_5error_2set_error’:
gen/pygame_sdl2.error.c:1072:3: error: format not a string literal and no format arguments [-Werror=format-security]
   SDL_SetError(__pyx_t_3);
   ^
cc1: some warnings being treated as errors
error: command 'aarch64-linux-gnu-gcc' failed with exit status 1

Could you please take a look?  I presume you'll want to arrange for this
call to wind up as

   SDL_SetError("%s", __pyx_t_3);

Thanks!