Log message:
add bl3 for waffle

Log message:
Import waffle-1.5.2 as wip/waffle.

Waffle is a cross-platform C library that allows one to defer selection of an
OpenGL API and window system until runtime. For example, on Linux, Waffle
enables an application to select X11/EGL with an OpenGL 3.3 core profile,
Wayland with OpenGL ES2, and other window system / API combinations.

Waffle's immediate goal is to enable Piglit, Mesa's OpenGL test suite, to test
multiple OpenGL flavors in a cross-platform way. However, Waffle's design does
not preclude it from being useful to other projects.