mbstring is a non-default extension. This
means it is not enabled by default. You must explicitly enable the
module with the configure option. See the Install section for details.
The following configure options are related to
the mbstring module.
–enable-mbstring : Enable
mbstring functions. This option is required to use
necessary for mbstring. libmbfl is bundled with mbstring.
Before PHP 7.3.0, if libmbfl is
already installed on the system, –with-libmbfl[=DIR] can be specified
to use the installed library.
–disable-mbregex : Disable regular
expression functions with multibyte character support.
necessary for the regular expression functions with multibyte
character support. Oniguruma is
bundled with mbstring. As of PHP 5.4.0, if Oniguruma is already installed on the system,
–with-onig[=DIR] can be
specified to use the installed library.
As of PHP 5.4.0 it is possible to disable the
multibyte regex backtrack check by specifying –disable-mbregex-backtrack .