Building release 0.5.0 on OpenBSD 7.0 fails with `ld: error: undefined symbol: backtrace`

[proditis]

Hi,

I tried building twemproxy-0.5.0.tar.gz on OpenBSD 7.0 following the README but the build process stops with the following error.

libtool: link: cc -fno-strict-aliasing -Wall -Wshadow -Wpointer-arith -Winline -Wunused-function -Wunused-variable -Wunused-value -Wno-unused-parameter -Wno-unused-value -Wconversion -Wsign-compare -Wstrict-prototypes -Wmissing-prototypes -Wredundant-decls -Wmissing-declarations -Wno-format-zero-length -g -O2 -rdynamic -o test_all test_all.o nc_core.o nc_connection.o nc_client.o nc_server.o nc_proxy.o nc_message.o nc_request.o nc_response.o nc_mbuf.o nc_conf.o nc_stats.o nc_signal.o nc_rbtree.o nc_log.o nc_string.o nc_array.o nc_util.o  ../src/hashkit/libhashkit.a ../src/proto/libproto.a ../src/event/libevent.a ../contrib/yaml-0.2.5/src/.libs/libyaml.a -lpthread -lm
ld: error: undefined symbol: backtrace
>>> referenced by nc_util.c:293
>>>               nc_util.o:(nc_stacktrace)
>>> referenced by nc_util.c:316
>>>               nc_util.o:(nc_stacktrace_fd)

ld: error: undefined symbol: backtrace_symbols
>>> referenced by nc_util.c:294
>>>               nc_util.o:(nc_stacktrace)

ld: error: undefined symbol: backtrace_symbols_fd
>>> referenced by nc_util.c:317
>>>               nc_util.o:(nc_stacktrace_fd)
cc: error: linker command failed with exit code 1 (use -v to see invocation)
gmake[3]: *** [Makefile:780: test_all] Error 1
gmake[3]: Leaving directory '/root/twemproxy-0.5.0/src'
gmake[2]: *** [Makefile:848: all-recursive] Error 1
gmake[2]: Leaving directory '/root/twemproxy-0.5.0/src'
gmake[1]: *** [Makefile:483: all-recursive] Error 1
gmake[1]: Leaving directory '/root/twemproxy-0.5.0'
gmake: *** [Makefile:372: all] Error 2

A quick search helped in solving this and complete the build, by adding -lexecinfo to the LIBS

./configure LIBS=-lexecinfo

I used info from this (non related to this project) issue koka-lang/libmprompt#5 which helped me in solving it.

If anyone can do a similar fix on twemproxy, that would be awesome 😃

[yuerugou54]

马晓栋已经收到您的来件，谢谢!