Buildroot compile error, librt.so: undefined reference to

I'm trying to compile a [Buildroot](https://bellard.org/tinyemu/buildroot-riscv-2018-10-20.tar.gz) image using a preconfigured builtin _defconfig file... More specific the riscv64_xwin_defconfig which is a simple setup for a riscv64 image with Xorg builtin. Since it's a rather old build i'm doing this inside a Fedora 23 Docker container which has gcc version 5.3.1, i don't think this is a problem since i can successfully build the non-Xwin riscv64 defconfig just fine The problem resides when the Makefile tries to build the specific package "eudev-3.2" Here is the config.log:

configure:3158: $? = 1
configure:3178: checking whether the C compiler works
configure:3200: /home/buildroot-riscv-2018-10-20/output/host/usr/bin/riscv64-buildroot-linux-gnu-gcc -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64  -Os  -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64  conftest.c -lrt >&5
/home/buildroot-riscv-2018-10-20/output/host/usr/lib/gcc/riscv64-buildroot-linux-gnu/7.3.0/../../../../riscv64-buildroot-linux-gnu/bin/ld: warning: libpthread.so.0, needed by /home/buildroot-riscv-2018-10-20/output/host/usr/riscv64-buildroot-linux-gnu/sysroot/usr/lib64/lp64d/librt.so, not found (try using -rpath or -rpath-link)
/home/buildroot-riscv-2018-10-20/output/host/usr/riscv64-buildroot-linux-gnu/sysroot/usr/lib64/lp64d/librt.so: undefined reference to `__pthread_barrier_wait@GLIBC_PRIVATE'
/home/buildroot-riscv-2018-10-20/output/host/usr/riscv64-buildroot-linux-gnu/sysroot/usr/lib64/lp64d/librt.so: undefined reference to `pthread_attr_setstacksize@GLIBC_2.27'
/home/buildroot-riscv-2018-10-20/output/host/usr/riscv64-buildroot-linux-gnu/sysroot/usr/lib64/lp64d/librt.so: undefined reference to `__pthread_barrier_init@GLIBC_PRIVATE'
/home/buildroot-riscv-2018-10-20/output/host/usr/riscv64-buildroot-linux-gnu/sysroot/usr/lib64/lp64d/librt.so: undefined reference to `__pthread_unwind@GLIBC_PRIVATE'
/home/buildroot-riscv-2018-10-20/output/host/usr/riscv64-buildroot-linux-gnu/sysroot/usr/lib64/lp64d/librt.so: undefined reference to `pthread_create@GLIBC_2.27'
/home/buildroot-riscv-2018-10-20/output/host/usr/riscv64-buildroot-linux-gnu/sysroot/usr/lib64/lp64d/librt.so: undefined reference to `pthread_sigmask@GLIBC_2.27'
/home/buildroot-riscv-2018-10-20/output/host/usr/riscv64-buildroot-linux-gnu/sysroot/usr/lib64/lp64d/librt.so: undefined reference to `pthread_once@GLIBC_2.27'
/home/buildroot-riscv-2018-10-20/output/host/usr/riscv64-buildroot-linux-gnu/sysroot/usr/lib64/lp64d/librt.so: undefined reference to `__shm_directory@GLIBC_PRIVATE'
/home/buildroot-riscv-2018-10-20/output/host/usr/riscv64-buildroot-linux-gnu/sysroot/usr/lib64/lp64d/librt.so: undefined reference to `pthread_detach@GLIBC_2.27'
/home/buildroot-riscv-2018-10-20/output/host/usr/riscv64-buildroot-linux-gnu/sysroot/usr/lib64/lp64d/librt.so: undefined reference to `pthread_cancel@GLIBC_2.27'
/home/buildroot-riscv-2018-10-20/output/host/usr/riscv64-buildroot-linux-gnu/sysroot/usr/lib64/lp64d/librt.so: undefined reference to `__pthread_get_minstack@GLIBC_PRIVATE'
collect2: error: ld returned 1 exit status