There are some platform specific issues (particularly on clang/Darwin), and some bugs that originate either in CIL or the underlying compilers. Here's what we know about:
CIL issue (1). CIL fails on Gcc torture test pr15296.c: typedef int __attribute__ ((mode (__pointer__))) intptr_t;
CIL issue (2). CIL fails on __alignof__(void).
If you see syntax errors while loading standard include files (like this: /usr/include/bits/mathcalls-helper-functions.h[21:12-28] : syntax error) make sure you've included "tigress.h" at the top of every file.
C99 issue. Tigress supports the C99 language. Depending on your compiler, you may have to add a switch (such as -std=c99 for gcc) to indicate this.