I used the php73_* one because php-7.3.4 no longer exists, thought it would be the same. (want to stay on 7.3.4 so my coredumps continue to stay valid)
However, I have tried php-7.3.5 now, but it fails with the very same error message: Failed to initialize NSS library
Mock excerpt:
# mock --configdir=./mock -r el7x rebuild php-7.3.5-1.remi.src.rpm
INFO: mock.py version 1.4.15 starting (python version = 2.7.5)...
Start: init plugins
INFO: selinux disabled
Finish: init plugins
Start: run
INFO: Start(php-7.3.5-1.remi.src.rpm) Config(el7x)
Start: clean chroot
Finish: clean chroot
Start: chroot init
INFO: calling preinit hooks
INFO: enabled root cache
Start: unpacking root cache
Finish: unpacking root cache
INFO: enabled yum cache
Start: cleaning yum metadata
Finish: cleaning yum metadata
INFO: enabled ccache
INFO: enabled HW Info plugin
Mock Version: 1.4.15
INFO: Mock Version: 1.4.15
Start: yum update
Failed to set locale, defaulting to C
... snip yum update...
Finish: yum update
Finish: chroot init
Start: build phase for php-7.3.5-1.remi.src.rpm
Start: build setup for php-7.3.5-1.remi.src.rpm
ERROR: Exception(php-7.3.5-1.remi.src.rpm) Config(el7x) 0 minutes 31 seconds
INFO: Results and/or logs in: /var/lib/mock/el7x
ERROR: Command failed:
# /bin/rpm -Uvh --nodeps /builddir/build/originals/php-7.3.5-1.remi.src.rpm
cat /var/lib/mock/el7x/root.log:
...
DEBUG util.py:585: python2-rpm-macros.noarch 0:3-24.el7
DEBUG util.py:732: Child return code was: 0
DEBUG util.py:222: touching file: /dev/shm/el7x/root/.initialized
DEBUG util.py:751: child environment: None
DEBUG util.py:677: Executing command: ['/bin/rpm', '-Uvh', '--nodeps', '/builddir/build/originals/php-7.3.5-1.remi.src.rpm'] with env {'LANG': 'en_US.UTF-8', 'TERM': 'vt100', 'SHELL': '/bin/bash', 'HOSTNAME': 'mock', 'PROMPT_COMMAND': 'printf "\\033]0;<mock-chroot>\\007"', 'PATH': '/usr/bin:/bin:/usr/sbin:/sbin', 'CCACHE_DIR': '/var/tmp/ccache', 'PS1': '<mock-chroot> \\s-\\v\\$ ', 'HOME': '/builddir', 'CCACHE_UMASK': '002'} and shell False
DEBUG util.py:583: BUILDSTDERR: error: Failed to initialize NSS library
DEBUG util.py:732: Child return code was: 1
...