$ spack install py-pyyaml
==> Error: Failed to install py-pyyaml due to ChildError: ProcessError: Command exited with status 1:
    '/home/hsf/spack/opt/spack/linux-centos7-sandybridge/gcc-8.3.1/python-3.7.7-oqdlfukk7v3iajirursoemgwjz4uq6uc/bin/python3.7' '-s' 'setup.py' '--no-user-cfg' '--with-libyaml' 'build'
3 errors found in build log:
     425    In file included from ext/_yaml.h:2,
     426                     from ext/_yaml.c:596:
     427    /home/hsf/spack/opt/spack/linux-centos7-sandybridge/gcc-8.3.1/libyaml-0.2.4-k46pfvmdak4ogt5qbu34cdkjtw4yjey5/include/yaml.h:635
            :1: note: expected 'const yaml_char_t *' {aka 'const unsigned char *'} but argument is of type 'char *'
     428     yaml_mapping_start_event_initialize(yaml_event_t *event,
     429     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     430    /opt/rh/devtoolset-8/root/usr/bin/gcc -pthread -shared -L/home/hsf/spack/opt/spack/linux-centos7-sandybridge/gcc-8.3.1/gettext-
            0.20.2-ywb257jdmwqy5gwssz6opqhqmjmnfpkh/lib -L/home/hsf/spack/opt/spack/linux-centos7-sandybridge/gcc-8.3.1/readline-8.0-qfr2d6
            nrzui4pihmumw2ngs5oezg2ebx/lib -L/home/hsf/spack/opt/spack/linux-centos7-sandybridge/gcc-8.3.1/ncurses-6.2-gy7fmfawhiwde4tk4lwn
            vwppf6xg6nku/lib -L/home/hsf/spack/opt/spack/linux-centos7-sandybridge/gcc-8.3.1/openssl-1.1.1g-73vqdkaryyg356e2skc7uu5foyllury
            y/lib -L/home/hsf/spack/opt/spack/linux-centos7-sandybridge/gcc-8.3.1/sqlite-3.31.1-5lrgvo7dtj6p4m2gv4d5gy7ecpshet3o/lib -L/hom
            e/hsf/spack/opt/spack/linux-centos7-sandybridge/gcc-8.3.1/gdbm-1.18.1-rw5vcezglu4vrccrvzt7u3vormfpnslk/lib -L/home/hsf/spack/op
            t/spack/linux-centos7-sandybridge/gcc-8.3.1/zlib-1.2.11-j2ucagtfig5spujohz2kfvt6bvqczkoa/lib -L/home/hsf/spack/opt/spack/linux-
            centos7-sandybridge/gcc-8.3.1/bzip2-1.0.8-ipfmbxrjzthhecv4mf3ecwi6jp5nlks7/lib -L/home/hsf/spack/opt/spack/linux-centos7-sandyb
            ridge/gcc-8.3.1/xz-5.2.5-ssqjpbn5vti7tluiwqo3pxbgdx2d4p6x/lib -L/home/hsf/spack/opt/spack/linux-centos7-sandybridge/gcc-8.3.1/e
            xpat-2.2.9-bijlnz6u5vp3oy35osxfghvelwbl4gok/lib -L/home/hsf/spack/opt/spack/linux-centos7-sandybridge/gcc-8.3.1/libffi-3.3-a557
            3cu6i6sycxun36p6ahlpvfxuy7kx/lib64 build/temp.linux-x86_64-3.7/ext/_yaml.o -L/home/hsf/spack/opt/spack/linux-centos7-sandybridg
            e/gcc-8.3.1/python-3.7.7-oqdlfukk7v3iajirursoemgwjz4uq6uc/lib -lyaml -lpython3.7m -o build/lib.linux-x86_64-3.7/_yaml.cpython-3
            7m-x86_64-linux-gnu.so
  >> 431    /opt/rh/devtoolset-8/root/usr/libexec/gcc/x86_64-redhat-linux/8/ld: cannot find -lyaml
  >> 432    collect2: error: ld returned 1 exit status
     433    /home/hsf/spack/opt/spack/linux-centos7-sandybridge/gcc-8.3.1/python-3.7.7-oqdlfukk7v3iajirursoemgwjz4uq6uc/lib/python3.7/distu
            tils/dist.py:274: UserWarning: Unknown distribution option: 'python_requires'
     434      warnings.warn(msg)
  >> 435    error: command '/opt/rh/devtoolset-8/root/usr/bin/gcc' failed with exit status 1

$ spack debug report
* **Spack:** 0.14.2-1047-ff6a0fc
* **Python:** 3.6.8
* **Platform:** linux-centos7-sandybridge