build is broken on CentOS 6

[chipitsine]

cc -Iinclude -Iebtree -Wall -Wextra  -O2 -g -fno-strict-aliasing -Wdeclaration-after-statement -fwrapv  -Wno-unused-label -Wno-sign-compare -Wno-unused-parameter -Wno-old-style-declaration -Wno-ignored-qualifiers -Wno-clobbered -Wno-missing-field-initializers     -Wtype-limits           -DUSE_EPOLL    -DUSE_NETFILTER -DUSE_PCRE    -DUSE_POLL  -DUSE_THREAD     -DUSE_TPROXY -DUSE_LINUX_TPROXY -DUSE_LINUX_SPLICE -DUSE_LIBCRYPT -DUSE_CRYPT_H  -DUSE_GETADDRINFO -DUSE_OPENSSL  -DUSE_FUTEX -DUSE_ACCEPT4  -DUSE_ZLIB  -DUSE_CPU_AFFINITY   -DUSE_DL -DUSE_RT      -DUSE_PRCTL -DUSE_THREAD_DUMP    -DUSE_PCRE -I/usr/include  -DCONFIG_HAPROXY_VERSION=\"2.2-dev0\" -DCONFIG_HAPROXY_DATE=\"2019/11/25\" -c -o ebtree/ebistree.o ebtree/ebistree.c
cc  -g -o haproxy src/ev_poll.o src/ev_epoll.o src/ssl_sock.o src/mux_h2.o src/stream.o src/mux_fcgi.o src/cfgparse-listen.o src/http_ana.o src/stats.o src/mux_h1.o src/flt_spoe.o src/server.o src/cfgparse.o src/checks.o src/backend.o src/log.o src/peers.o src/cli.o src/haproxy.o src/stick_table.o src/standard.o src/sample.o src/proxy.o src/stream_interface.o src/pattern.o src/dns.o src/proto_tcp.o src/listener.o src/cfgparse-global.o src/h1.o src/http_rules.o src/http_fetch.o src/cache.o src/session.o src/fcgi-app.o src/connection.o src/tcp_rules.o src/filters.o src/task.o src/mworker.o src/map.o src/h1_htx.o src/trace.o src/flt_trace.o src/acl.o src/http_htx.o src/flt_http_comp.o src/payload.o src/vars.o src/debug.o src/mux_pt.o src/http_act.o src/h2.o src/queue.o src/fd.o src/proto_uxst.o src/lb_chash.o src/ring.o src/frontend.o src/raw_sock.o src/xprt_handshake.o src/htx.o src/memory.o src/applet.o src/channel.o src/signal.o src/lb_fwrr.o src/ev_select.o src/sink.o src/http_conv.o src/proto_sockpair.o src/mworker-prog.o src/activity.o src/lb_fwlc.o src/http.o src/lb_fas.o src/uri_auth.o src/hathreads.o src/regex.o src/auth.o src/buffer.o src/compression.o src/proto_udp.o src/lb_map.o src/chunk.o src/wdt.o src/hpack-dec.o src/action.o src/xxhash.o src/pipe.o src/shctx.o src/hpack-tbl.o src/http_acl.o src/sha1.o src/time.o src/hpack-enc.o src/fcgi.o src/arg.o src/base64.o src/protocol.o src/freq_ctr.o src/lru.o src/hpack-huff.o src/dict.o src/hash.o src/mailers.o src/version.o ebtree/ebtree.o ebtree/eb32sctree.o ebtree/eb32tree.o ebtree/eb64tree.o ebtree/ebmbtree.o ebtree/ebsttree.o ebtree/ebimtree.o ebtree/ebistree.o   -lcrypt  -lz -ldl -lpthread -lrt  -lssl -lcrypto -ldl -L/usr/lib -lpcreposix -lpcre 
src/ssl_sock.o: In function `ssl_set_cert_crl_file':
/tmp/cirrus-ci-build/src/ssl_sock.c:421: undefined reference to `X509_STORE_get0_objects'
/tmp/cirrus-ci-build/src/ssl_sock.c:429: undefined reference to `X509_OBJECT_get0_X509_CRL'
/tmp/cirrus-ci-build/src/ssl_sock.c:424: undefined reference to `X509_OBJECT_get_type'
/tmp/cirrus-ci-build/src/ssl_sock.c:426: undefined reference to `X509_OBJECT_get0_X509'
src/ssl_sock.o: In function `ssl_get_client_ca_file':
/tmp/cirrus-ci-build/src/ssl_sock.c:478: undefined reference to `X509_STORE_get0_objects'
/tmp/cirrus-ci-build/src/ssl_sock.c:480: undefined reference to `X509_OBJECT_get0_X509'
collect2: ld returned 1 exit status
make: *** [haproxy] Error 1

Exit status: 2

[lukastribus]

CCing @ehocdet

[ehocdet]

it's a openssl < 1.1.0 compatibility pbl, i will check this.