Restore pthread LDFLAG in examples

[eduar-hte]

what

Restore the pthread LDFLAG to build the following examples: multithread & reading_logs_with_offset

why

I removed this flag from the reading_logs_with_offset in commit 293cd21 after replacing usage of pthreads with C++'s std::thread. Additionally, I didn't add that flag either to the multithread example added in commit 4bf9616 for the same reason.

However, I'm getting the following error when building both of these projects in a Debian container:

/usr/bin/ld: multithread-multithread.o: undefined reference to symbol 'pthread_create@@GLIBC_2.2.5'
/usr/bin/ld: /lib/x86_64-linux-gnu/libpthread.so.0: error adding symbols: DSO missing from command line

NOTE: It's curious that this doesn't happen when building the projects in all the non-Windows environments of the Quality Assurance workflow (which uses the same configuration) and thus wasn't detected before integrating PR #3216. 🤷‍♂️

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud

[airween]

However, I'm getting the following error when building both of these projects in a Debian container:

/usr/bin/ld: multithread-multithread.o: undefined reference to symbol 'pthread_create@@GLIBC_2.2.5'
/usr/bin/ld: /lib/x86_64-linux-gnu/libpthread.so.0: error adding symbols: DSO missing from command line

hmm, it's very interesting.

NOTE: It's curious that this doesn't happen when building the projects in all the non-Windows environments of the Quality Assurance workflow (which uses the same configuration) and thus wasn't detected before integrating PR #3216. 🤷‍♂️

Yes. When I saw you removed that LDFLAG I though it's a bit weird but the regression tests passed so it's no problem.

Btw here is a log snippet from the CI:

https://github.com/owasp-modsecurity/ModSecurity/actions/runs/10324047165/job/28582691805?pr=3216#step:9:873

And this is my build process (without applying this patch):

g++ -std=c++17 -DHAVE_CONFIG_H -I. -I../../src   -I../../headers -I../.. -g -I../others -fPIC -O3 -DWITH_CURL_SSLVERSION_TLSv1_2 -DWITH_CURL -DWITH_GEOIP -I/usr/include/  -DWITH_MAXMIND -I/usr/include/x86_64-linux-gnu  -UNDEBUG  -DWITH_YAJL  -I/usr/include  -DWITH_LUA -DWITH_LUA_5_3 -I/usr/include/lua5.3  -I/usr/include/libxml2  -DWITH_LIBXML2   -O0 -g -DWITH_PCRE2 -MT read-read.o -MD -MP -MF .deps/read-read.Tpo -c -o read-read.o `test -f 'read.cc' || echo './'`read.cc
mv -f .deps/read-read.Tpo .deps/read-read.Po
/bin/bash ../../libtool  --tag=CXX   --mode=link g++ -std=c++17  -O0 -g -DWITH_PCRE2 -L../../src/.libs/  -lmodsecurity -lm -lstdc++  -L/usr/lib/x86_64-linux-gnu/ -L/usr/lib/x86_64-linux-gnu/    -o read read-read.o -lcurl -lGeoIP  -lmaxminddb  -lrt   -lxml2  -llmdb  -llua5.3  -lfuzzy -lyajl  
libtool: link: g++ -std=c++17 -O0 -g -DWITH_PCRE2 -o .libs/read read-read.o  -L../../src/.libs/ /home/airween/src/ModSecurity/src/.libs/libmodsecurity.so -lm -lstdc++ -L/usr/lib/x86_64-linux-gnu/ -lcurl -lGeoIP -lmaxminddb -lrt -lxml2 -llmdb -llua5.3 -lfuzzy -lyajl

on a Debian SID.