Looks like GCC maps "stat" (and fstat/lstat) to an inline function, which would explain why it doesn't show up in libc.so:

extern __inline__ int __attribute__ ((__nothrow__)) stat (__const char *__path, struct stat *__statbuf ) { return __xstat (3, __path, __statbuf); }

Library.Handler.invoke or Function.invoke seem like the logical points to tweak the invocation. If this is common, it might make sense to make a function mogrifier option for the library.