bpftool disassembler optionally uses LLVM to improve its capabilities.
Unfortunately, even if llvm-devel is installed, the feature detection of
LLVM doesn't work:
Auto-detecting system features:
... clang-bpf-co-re: [ on ]
... llvm: [ OFF ]
... libcap: [ on ]
... libbfd: [ on ]
The reason is that the feature detection tries to compile a simple C++
program and link it against libLLVM which fails as LDFLAGS contains -pie
while CXXFLAGS does not contain -fpie.
Fix this by setting EXTRA_CXXFLAGS from the bpftool build.
Signed-off-by: Viktor Malik <vmalik@redhat.com>
