The stringi package depends on the ICU4C >= 50 library.
If you build the package from sources and either:
* these requirements are not met (check out http://site.icu-project.org/download
   or e.g. the 'libicu-devel' rpm package on Fedora or 'libicu-dev' on Ubuntu),
* pkg-config cannot find proper build settings for ICU-based projects, or
* R CMD INSTALL is called with --configure-args='--disable-pkg-config',
then the library will be built together with stringi
(a custom subset of ICU4C 52.1 is shipped with the package).


You are encouraged to check whether the ICU data library (icudt)
has been successfully installed by calling:

> library('stringi')
> stri_install_check()

This will also make you sure that ICU has detected your locale and native
encoding properly.