From PHP version 7.3, 'pcre2' is used instead of 'pcre'. It is bundled with the PHP source, or a preinstalled pcre2 can be used if it was compiled with these configure-options:
--enable-shared --enable-unicode --enable-jit
If you want to use preinstalled pcre2 with PHP, use configure-options --with-pcre-dir=<path> and --with-pcre-regex=<path> (I don't know why there is two of them).