to link to the external oniguruma library.
- Prevent libmbfl files from being installed when --with-libmbfl is specified.
- Fixed mb_ereg_replace() to work with unicode strings.
. Supports various encodings such as BIG5, GB2312 and ISO-8859-*
. Fixes bug #26677 (mbstring compile errors with IRIX)
. Many thanks to K.Kosako.
- Remove redundant files that are not relevant to the build.