Ref T13296. On macOS with PHP 7.3.x, PCRE can segfault during calls to "preg_match()" or during process shutdown.
Disabling "pcre.jit" appears to work around this issue. Some casual Googling suggests that the JIT does not dramatically improve performance (~10%?) and we aren't PCRE-bound anyway, so prefer "not crashing" over "questionable performance improvements" on all systems for now.