FindVorbis: Link ogg in static builds

[fwcd]

We have to link libogg into libvorbis when building static binaries on Linux, see e.g. this build:

/usr/bin/ld: /home/runner/work/m1xxx/m1xxx/vcpkg/installed/x64-linux/lib/libvorbis.a(block.c.o): in function `vorbis_block_init':
block.c:(.text+0x3f8): undefined reference to `oggpack_writeinit'
/usr/bin/ld: block.c:(.text+0x415): undefined reference to `oggpack_writeinit'
/usr/bin/ld: /home/runner/work/m1xxx/m1xxx/vcpkg/installed/x64-linux/lib/libvorbis.a(block.c.o): in function `vorbis_block_clear':
block.c:(.text+0x58a): undefined reference to `oggpack_writeclear'
/usr/bin/ld: /home/runner/work/m1xxx/m1xxx/vcpkg/installed/x64-linux/lib/libvorbis.a(analysis.c.o): in function `vorbis_analysis':
analysis.c:(.text+0x48): undefined reference to `oggpack_reset'
...

[fwcd]

Seems to work, there are no more oggpack_* linker errors in this build.

[daschuer]

LGTM