glsl: Reject shaders that contain static recursion

glsl: Reject shaders that contain static recursion

The GLSL 1.20 and later specs say:

    "Recursion is not allowed, not even statically. Static recursion is
    present if the static function call graph of the program contains
    cycles."

Recursion is detected and rejected both a compile-time and at
link-time.  The complie-time check happens to detect some cases that
may be removed by various optimization passes.  The spec doesn't seem
to allow this, but other vendors (e.g., NVIDIA) appear to only check
at link-time after all optimizations.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=33885
Reviewed-by: Paul Berry <stereotype441@gmail.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>