dlfcn-util: add static asserts ensuring our sym_xyz() func ptrs match the types from the official headers

Make sure that the sym_xyz function pointers have the types that the
functions we'll assign them have.

And of course, this found a number of incompatibilities right-away, in
particular in the bpf hookup.

(Doing this will trigger deprecation warnings from libbpf. I simply
turned them off locally now, since we are well aware of what we are
doing in that regard.)

There's one return type fix (bool → int), that actually matters I think,
as it might have created an incompatibility on some archs.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/shared/bpf-dlopen.h b/src/shared/bpf-dlopen.h
index 95951e63e0..0750abc56b 100644
--- a/src/shared/bpf-dlopen.h
+++ b/src/shared/bpf-dlopen.h
@@ -8,8 +8,8 @@
 
 #include "bpf-compat.h"
 
-extern struct bpf_link* (*sym_bpf_program__attach_cgroup)(struct bpf_program *, int);
-extern struct bpf_link* (*sym_bpf_program__attach_lsm)(struct bpf_program *);
+extern struct bpf_link* (*sym_bpf_program__attach_cgroup)(const struct bpf_program *, int);
+extern struct bpf_link* (*sym_bpf_program__attach_lsm)(const struct bpf_program *);
 extern int (*sym_bpf_link__fd)(const struct bpf_link *);
 extern int (*sym_bpf_link__destroy)(struct bpf_link *);
 extern int (*sym_bpf_map__fd)(const struct bpf_map *);