ebpf: only include in system emulators

eBPF files are being included in user emulators, which is useless and
also breaks compilation because ebpf/trace-events is only processed
if a system emulator is included in the build.

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/566
Signed-off-by: Paolo Bonzini <[email protected]>
Signed-off-by: Jason Wang <[email protected]>

Author: bonzini

ebpf/meson.build

@@ -1 +1 @@
-common_ss.add(when: libbpf, if_true: files('ebpf_rss.c'), if_false: files('ebpf_rss-stub.c'))
+softmmu_ss.add(when: libbpf, if_true: files('ebpf_rss.c'), if_false: files('ebpf_rss-stub.c'))