games/moonlight-embedded: Unbreak with GCC10/Clang11 (-fno-common default)

ld: error: duplicate symbol: inputAdded

defined at config.c

CMakeFiles/moonlight.dir/src/config.c.o:(inputAdded)

defined at main.c

CMakeFiles/moonlight.dir/src/main.c.o:(.bss+0x0)

ld: error: duplicate symbol: mutex

defined at main.c

CMakeFiles/moonlight.dir/src/main.c.o:(mutex)

defined at sdl.c

CMakeFiles/moonlight.dir/src/sdl.c.o:(.bss+0x28)

ld: error: duplicate symbol: sdlCurrentFrame

defined at main.c

CMakeFiles/moonlight.dir/src/main.c.o:(sdlCurrentFrame)

defined at sdl.c

CMakeFiles/moonlight.dir/src/sdl.c.o:(.bss+0x4)

ld: error: duplicate symbol: sdlNextFrame

defined at main.c

CMakeFiles/moonlight.dir/src/main.c.o:(sdlNextFrame)

defined at sdl.c

CMakeFiles/moonlight.dir/src/sdl.c.o:(.bss+0x0)

ld: error: duplicate symbol: mutex

defined at main.c

CMakeFiles/moonlight.dir/src/main.c.o:(mutex)

defined at sdl.c

CMakeFiles/moonlight.dir/src/video/sdl.c.o:(.bss+0x0)

ld: error: duplicate symbol: sdlCurrentFrame

defined at main.c

CMakeFiles/moonlight.dir/src/main.c.o:(sdlCurrentFrame)

defined at sdl.c

CMakeFiles/moonlight.dir/src/video/sdl.c.o:(.bss+0x8)

ld: error: duplicate symbol: sdlNextFrame

defined at main.c

CMakeFiles/moonlight.dir/src/main.c.o:(sdlNextFrame)

defined at sdl.c

CMakeFiles/moonlight.dir/src/video/sdl.c.o:(.bss+0xC)

ld: error: duplicate symbol: mutex

defined at main.c

CMakeFiles/moonlight.dir/src/main.c.o:(mutex)

defined at sdl.c

CMakeFiles/moonlight.dir/src/input/sdl.c.o:(.bss+0xB8)

ld: error: duplicate symbol: sdlCurrentFrame

defined at main.c

CMakeFiles/moonlight.dir/src/main.c.o:(sdlCurrentFrame)

defined at sdl.c

CMakeFiles/moonlight.dir/src/input/sdl.c.o:(.bss+0xC0)

ld: error: duplicate symbol: sdlNextFrame

defined at main.c

CMakeFiles/moonlight.dir/src/main.c.o:(sdlNextFrame)

defined at sdl.c

CMakeFiles/moonlight.dir/src/input/sdl.c.o:(.bss+0xC4)