Fix vtest build by depending on libvirglrenderer_dep

Build was broken by 1e581b6b, #152 (closed)

To reproduce

export CC=clang
meson build/
meson configure build/ -Dfuzzer=true
ninja -C build

[48/50] Linking target vtest/vtest_fuzzer.
FAILED: vtest/vtest_fuzzer 
clang  -o vtest/vtest_fuzzer 'vtest/63b2dfc@@vtest_fuzzer@exe/vtest_fuzzer.c.o' 'vtest/63b2dfc@@virgl_test_server@exe/util.c.o' 'vtest/63b2dfc@@virgl_test_server@exe/vtest_shm.c.o' 'vtest/63b2dfc@@virgl_test_server@exe/vtest_renderer.c.o' -Wl,--no-undefined -Wl,--as-needed -Wl,-O1 -Wl,--start-group src/libvirgl.a src/gallium/libgallium.a -fsanitize=address -fsanitize=fuzzer /usr/local/lib/x86_64-linux-gnu/libepoxy.so /usr/lib/x86_64-linux-gnu/libdrm.so -pthread -lm /usr/lib/x86_64-linux-gnu/libgbm.so /usr/lib/x86_64-linux-gnu/libX11.so -Wl,--end-group '-Wl,-rpath,$ORIGIN/../src:$ORIGIN/../src/gallium:/usr/local/lib/x86_64-linux-gnu' -Wl,-rpath-link,/media/woodychow/disk0/virglrenderer/build/src -Wl,-rpath-link,/media/woodychow/disk0/virglrenderer/build/src/gallium -Wl,-rpath-link,/usr/local/lib/x86_64-linux-gnu
/usr/bin/ld: vtest/63b2dfc@@virgl_test_server@exe/vtest_renderer.c.o: in function `vtest_create_renderer':
vtest_renderer.c:(.text+0x1e0): undefined reference to `virgl_renderer_init'
/usr/bin/ld: vtest_renderer.c:(.text+0x239): undefined reference to `virgl_renderer_context_create'
/usr/bin/ld: vtest/63b2dfc@@virgl_test_server@exe/vtest_renderer.c.o: in function `vtest_destroy_renderer':
vtest_renderer.c:(.text+0x477): undefined reference to `virgl_renderer_context_destroy'
/usr/bin/ld: vtest_renderer.c:(.text+0x481): undefined reference to `virgl_renderer_cleanup'
/usr/bin/ld: vtest/63b2dfc@@virgl_test_server@exe/vtest_renderer.c.o: in function `vtest_send_caps2':
vtest_renderer.c:(.text+0x4da): undefined reference to `virgl_renderer_get_cap_set'
/usr/bin/ld: vtest_renderer.c:(.text+0x514): undefined reference to `virgl_renderer_fill_caps'
/usr/bin/ld: vtest/63b2dfc@@virgl_test_server@exe/vtest_renderer.c.o: in function `vtest_send_caps':
vtest_renderer.c:(.text+0x5da): undefined reference to `virgl_renderer_get_cap_set'
/usr/bin/ld: vtest_renderer.c:(.text+0x602): undefined reference to `virgl_renderer_fill_caps'
/usr/bin/ld: vtest/63b2dfc@@virgl_test_server@exe/vtest_renderer.c.o: in function `vtest_create_resource':
vtest_renderer.c:(.text+0x700): undefined reference to `virgl_renderer_resource_create'
/usr/bin/ld: vtest_renderer.c:(.text+0x70f): undefined reference to `virgl_renderer_ctx_attach_resource'
/usr/bin/ld: vtest/63b2dfc@@virgl_test_server@exe/vtest_renderer.c.o: in function `vtest_create_resource2':
vtest_renderer.c:(.text+0x7ac): undefined reference to `virgl_renderer_resource_create'
/usr/bin/ld: vtest_renderer.c:(.text+0x7e1): undefined reference to `virgl_renderer_ctx_attach_resource'
/usr/bin/ld: vtest_renderer.c:(.text+0x941): undefined reference to `virgl_renderer_resource_attach_iov'
/usr/bin/ld: vtest/63b2dfc@@virgl_test_server@exe/vtest_renderer.c.o: in function `vtest_resource_unref':
vtest_renderer.c:(.text+0x9df): undefined reference to `virgl_renderer_ctx_attach_resource'
/usr/bin/ld: vtest_renderer.c:(.text+0x9ed): undefined reference to `virgl_renderer_resource_detach_iov'
/usr/bin/ld: vtest_renderer.c:(.text+0xa03): undefined reference to `virgl_renderer_resource_unref'
/usr/bin/ld: vtest/63b2dfc@@virgl_test_server@exe/vtest_renderer.c.o: in function `vtest_submit_cmd':
vtest_renderer.c:(.text+0xa71): undefined reference to `virgl_renderer_submit_cmd'
/usr/bin/ld: vtest/63b2dfc@@virgl_test_server@exe/vtest_renderer.c.o: in function `vtest_transfer_get':
vtest_renderer.c:(.text+0xb4f): undefined reference to `virgl_renderer_transfer_read_iov'
/usr/bin/ld: vtest/63b2dfc@@virgl_test_server@exe/vtest_renderer.c.o: in function `vtest_transfer_put':
vtest_renderer.c:(.text+0xd5f): undefined reference to `virgl_renderer_transfer_write_iov'
/usr/bin/ld: vtest/63b2dfc@@virgl_test_server@exe/vtest_renderer.c.o: in function `vtest_transfer_get2':
vtest_renderer.c:(.text+0xeb9): undefined reference to `virgl_renderer_transfer_read_iov'
/usr/bin/ld: vtest/63b2dfc@@virgl_test_server@exe/vtest_renderer.c.o: in function `vtest_transfer_put2':
vtest_renderer.c:(.text+0x1013): undefined reference to `virgl_renderer_transfer_write_iov'
/usr/bin/ld: vtest/63b2dfc@@virgl_test_server@exe/vtest_renderer.c.o: in function `vtest_resource_busy_wait':
vtest_renderer.c:(.text+0x1101): undefined reference to `virgl_renderer_get_poll_fd'
/usr/bin/ld: vtest_renderer.c:(.text+0x1112): undefined reference to `virgl_renderer_poll'
/usr/bin/ld: vtest/63b2dfc@@virgl_test_server@exe/vtest_renderer.c.o: in function `vtest_renderer_create_fence':
vtest_renderer.c:(.text+0x11f6): undefined reference to `virgl_renderer_create_fence'
/usr/bin/ld: vtest/63b2dfc@@virgl_test_server@exe/vtest_renderer.c.o: in function `vtest_poll':
vtest_renderer.c:(.text+0x1202): undefined reference to `virgl_renderer_poll'
clang: error: linker command failed with exit code 1 (use -v to see invocation)
[49/50] Generating symbol file 'src/25a6634@@virglrenderer@sha/libvirglrenderer.so.1.4.1.symbols'.
ninja: build stopped: subcommand failed.