perf build: Suppress openssl v3 deprecation warnings in libcrypto feature test

With OpenSSL v3 installed, the libcrypto feature check fails as it use the
deprecated MD5_* API (and is compiled with -Werror). The error message is
as follows.

$ make tools/perf
```
Makefile.config:778: No libcrypto.h found, disables jitted code injection,
please install openssl-devel or libssl-dev

Auto-detecting system features:
...                         dwarf: [ on  ]
...            dwarf_getlocations: [ on  ]
...                         glibc: [ on  ]
...                        libbfd: [ on  ]
...                libbfd-buildid: [ on  ]
...                        libcap: [ on  ]
...                        libelf: [ on  ]
...                       libnuma: [ on  ]
...        numa_num_possible_cpus: [ on  ]
...                       libperl: [ on  ]
...                     libpython: [ on  ]
...                     libcrypto: [ OFF ]
...                     libunwind: [ on  ]
...            libdw-dwarf-unwind: [ on  ]
...                          zlib: [ on  ]
...                          lzma: [ on  ]
...                     get_cpuid: [ on  ]
...                           bpf: [ on  ]
...                        libaio: [ on  ]
...                       libzstd: [ on  ]
...        disassembler-four-args: [ on  ]
```

This is very confusing because the suggested library (on my Ubuntu 20.04
it is libssl-dev) is already installed. As the test only checks for the
presence of libcrypto, this commit suppresses the deprecation warning to
allow the test to pass.

Signed-off-by: Zixuan Tan <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Cc: Andrii Nakryiko <[email protected]>
Cc: Daniel Borkmann <[email protected]>
Cc: John Fastabend <[email protected]>
Cc: KP Singh <[email protected]>
Cc: Martin KaFai Lau <[email protected]>
Cc: Nick Terrell <[email protected]>
Cc: Song Liu <[email protected]>
Cc: Yonghong Song <[email protected]>
Cc: [email protected]
Cc: [email protected]
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

diff --git a/tools/build/feature/test-libcrypto.c b/tools/build/feature/test-libcrypto.c
index a98174e0569c875554b28b68a367cf12c0138a75..31afff093d0bfaa612023cd8094b2f24a268ec51 100644 (file)
--- a/tools/build/feature/test-libcrypto.c
+++ b/tools/build/feature/test-libcrypto.c
@@ -2,6 +2,12 @@
 #include <openssl/sha.h>
 #include <openssl/md5.h>
 
+/*
+ * The MD5_* API have been deprecated since OpenSSL 3.0, which causes the
+ * feature test to fail silently. This is a workaround.
+ */
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+
 int main(void)
 {
        MD5_CTX context;