Significantly improved XIM support. Fixes Bugzilla #429. Selected notes from the patch's README: = FIXES = This patch fixes the above issues as follows. == X11 events == Moved XFilterEvent just after XNextEvent so that all events are passed to it. Also, XFilterEvent will receive masks indicated by IM through XNFilterEvents IC value as well as masks surpplied by SDL. X11_KeyRepeat is called between XNextEvent and XFilterEvent, after testing an event is a KeyRelease. I'm not 100% comfortable to do so, but I couldn't find a better timing to call it, and use of the function is inevitable. == Xutf8LookupString == Used a longer buffer to receive UTF-8 string. If it is insufficient, a dynamic storage of the requested size will be allocated. The initial size of the buffer is set to 32, because the Japanese text converted from the most widely used benchmark key sequence for Japanese IM, "WATASHINONAMAEHANAKANODESU." has ten Japanese characters in it, that occupies 30 bytes when encoded in UTF-8. == SDL_keysym.unicode == On Windows version of SDL implementation, SDL_keysym.unicode stores UTF-16 encoded unicode characters, one UTF-16 encoding unit per an SDL event. A Unicode supplementary characters are sent to an application as two events. (One with a high surrogate and another with a low surrogate.) The behavior seems reasonable since it is upward compatible with existing handling of BMP characters. I wrote a UTF-8 to UTF-16 conversion function for the purpose. It is designed with the execution speed in mind, having a minimum set of features that my patch requires.