Determining if the include file pthread.h exists failed with the following output:
Change Dir: /home/buildroot/autobuild/instance-0/output-1/build/open62541-v1.3.2/CMakeFiles/CMakeTmp

Run Build Command(s):/usr/bin/make -f Makefile cmTC_24dfc/fast && make[1]: Entering directory '/home/buildroot/autobuild/instance-0/output-1/build/open62541-v1.3.2/CMakeFiles/CMakeTmp'
/usr/bin/make  -f CMakeFiles/cmTC_24dfc.dir/build.make CMakeFiles/cmTC_24dfc.dir/build
make[2]: Entering directory '/home/buildroot/autobuild/instance-0/output-1/build/open62541-v1.3.2/CMakeFiles/CMakeTmp'
Building C object CMakeFiles/cmTC_24dfc.dir/CheckIncludeFile.c.o
/home/buildroot/autobuild/instance-0/output-1/host/bin/mips64el-buildroot-linux-uclibc-gcc --sysroot=/home/buildroot/autobuild/instance-0/output-1/host/mips64el-buildroot-linux-uclibc/sysroot   -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -O3 -g0 -static   -DNDEBUG -o CMakeFiles/cmTC_24dfc.dir/CheckIncludeFile.c.o -c /home/buildroot/autobuild/instance-0/output-1/build/open62541-v1.3.2/CMakeFiles/CMakeTmp/CheckIncludeFile.c
/home/buildroot/autobuild/instance-0/output-1/build/open62541-v1.3.2/CMakeFiles/CMakeTmp/CheckIncludeFile.c:1:10: fatal error: pthread.h: No such file or directory
    1 | #include <pthread.h>
      |          ^~~~~~~~~~~
compilation terminated.
CMakeFiles/cmTC_24dfc.dir/build.make:77: recipe for target 'CMakeFiles/cmTC_24dfc.dir/CheckIncludeFile.c.o' failed
make[2]: *** [CMakeFiles/cmTC_24dfc.dir/CheckIncludeFile.c.o] Error 1
make[2]: Leaving directory '/home/buildroot/autobuild/instance-0/output-1/build/open62541-v1.3.2/CMakeFiles/CMakeTmp'
Makefile:127: recipe for target 'cmTC_24dfc/fast' failed
make[1]: *** [cmTC_24dfc/fast] Error 2
make[1]: Leaving directory '/home/buildroot/autobuild/instance-0/output-1/build/open62541-v1.3.2/CMakeFiles/CMakeTmp'