The Crystal lib can only be linked to a specific version of ICU

[olbat]

For some reasons ^1,2,3, most distributions of ICU are compiled using the symbol renaming feature (a suffix containing the ICU version number is added to every symbols in shared objects).

It makes the task of creating a generic Crystal binding more difficult since ABIs of different versions of ICU are 100% incompatible.

For the moment the lib_icu binding has been generated against the version 52 of ICU making it incompatible with any other version of the library.

[olbat]

Here are some ideas to solve the issue:

1. Use a linker script to rename symbols at linking time
2. Generate^1,2 the binding at install time (via postinstall script in the shard ?)
3. Generate bindings for the N last versions of ICU (+ a binding without suffixes )
   and choose which one to load at compile time
4. Distribute a version of ICU sources with the library + compile it before the Crystal library
5. Wait for some "on-the-fly code generation" feature to be integrated in Crystal core

[olbat]

This topic is also discussed on Crystal's google group.

update: see https://gist.github.com/olbat/4a5d6d474efd54e14fbac317b3ae8819

[kostya]

there is also different so names for osx and linux, i write little binding here: https://github.com/kostya/icu/blob/master/src/icu/lib.cr, but it not solve suffixes