I encountered a compilation problem when installing ocs2

[yakousansan]

Describe the bug
Run Build Command(s):/usr/bin/make cmTC_53c66/fast && /usr/bin/make -f CMakeFiles/cmTC_53c66.dir/build.make CMakeFiles/cmTC_53c66.dir/build
make[1]: Entering directory '/opt/ocs2/ocs2_oc/build/CMakeFiles/CMakeTmp'
Building C object CMakeFiles/cmTC_53c66.dir/CheckFunctionExists.c.o
/usr/bin/cc -DCHECK_FUNCTION_EXISTS=pthread_create -o CMakeFiles/cmTC_53c66.dir/CheckFunctionExists.c.o -c /usr/share/cmake-3.16/Modules/CheckFunctionExists.c
Linking C executable cmTC_53c66
/usr/bin/cmake -E cmake_link_script CMakeFiles/cmTC_53c66.dir/link.txt --verbose=1
/usr/bin/cc -DCHECK_FUNCTION_EXISTS=pthread_create -rdynamic CMakeFiles/cmTC_53c66.dir/CheckFunctionExists.c.o -o cmTC_53c66 -lpthreads
/usr/bin/ld: cannot find -lpthreads
collect2: error: ld returned 1 exit status
make[1]: *** [CMakeFiles/cmTC_53c66.dir/build.make:87: cmTC_53c66] Error 1
make[1]: Leaving directory '/opt/ocs2/ocs2_oc/build/CMakeFiles/CMakeTmp'
make: *** [Makefile:121: cmTC_53c66/fast] Error 2

Screenshots

Desktop (please complete the following information):

• ubuntu20.04
• ROS 1Noetic Ninjemys
• All other related libraries are installed according to the official instructions